I have the same condition, but less severe. I think that one day I might grow out of it, but I know how to stop mixing reality from imagination. Keep your head straight. I know it’s hard, but step back from yourself and try your hardest to deduce what’s logical and what’s not probable when between your realistic and fictional world. There’s nothing wrong with having a creative mind. But again, take a step back. That’s a way to stop it from consuming your entire life. 

urg, it's quite possible i have this...i kinda find it unlikely though...eh, call it 50/50...yikes...

I'm not sure how much this will help, but.

You said that you just spent a few months without daydreaming. How did you do that? Is it possible to replicate? Because if you don't want to get worse, and you can replicate these conditions, try maybe doing it every other week. A week of daydreaming, a week without. Then maybe you can shorten the time frame - every five days, every three days, every other day. Hopefully at some point surpressing the daydreams will come naturally. It might take a lot of effort and it will go slowly, but if you really want to stop this that's my advice.

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Also, this is a warning to the general public - not necessarily you, ... . Before you go talking about whether or not you have this: be sure you check with a psychiatrist, go on medical websites, and ask yourself if you really have all these conditions. 

One website said that maladaptive daydreaming is a disorder that causes vivid and uncontrollable daydreams that can hamper a person's actions. Now, before you go diagnosing yourself, think about this: Psychology Today said that "everyone, or nearly everyone, reports daydreaming on a regular basis,
with studies indicating that as many as 96% of adults engage in having
at least one bout of daily fantasies." Daydreaming, even frequent daydreaming, is not the same. It's only if you accidentally go into a basically hours-long, incredibly vivid daydream - frequently - that you're displaying symptoms.

If you really think this refers to you, do more research. Go online and read about all the symptoms of this condition. Then, talk to your parents. If they agree with you, set up an appointment with a doctor or psychologist who can confirm your suspicions. Maladaptive daydreaming disorder isn't recognized as a real condition, and therefore you probably can't get an official diagnosis, but you will have an expert opinion and, hopefully, someone to help you along.

That... sounds like what I do, but amped up, intensified. I don't have strategies laid out to combat it, but I usually stop or slow down if somebody catches me acting out a scene or if I consider writing it down. So, maybe try writing you daydreams down? If not, I second St. Owl's suggestion that you try to recreate your daydream-free period. If you try and it doesn't work, try again with a lower goal: one month, one week, one day. 

It kind of sounds like what you're going through is dealing with an addiction, addicted to daydreaming, so maybe you could modify strategies normally applied to those, see if it helps. I don't know much about that, but the Internet exists, and you know how to use it.

Tell us what you choose to do and how it goes. Best of wishes and of luck! 

I have the same disorder, and I can relate. Something that helped me a lot was drawing my daydreams out, and keeping those drawings in a separate folder. This way I can differentiate from real life and my imagination. 

First off I want to say, I have no clue what to tell you, but I want to help you. So please hear me out.

Okay, so I daydream all the time. I love it and do it while going to sleep, moving around, working and pretty much any mindless task. But I don't allow myself to do it while I'm thinking. I don't know if this will work for you, but give it a whack. It is basically just like what St. Owl is saying  about structuring your day dreaming life, just a little less strict. I also agree with what she says. Also someone said something about writing your daydreams down? I agree with that as well, or drawing if you'd rather. Writing helps me keep my thoughts from flooding me like muddy water.
Also maybe try daydreaming about other things? Try creating characters in another world. You could create the world or use one from a book. Make them far from you. Make them evil and weird. Make them feel pain. Are those the sort of people you want to hang out with? This sounds really weird, but I'm suggesting you force your daydreams away from yourself by making them unpleasant. Or try creating a story. Let yourself daydream about it, but make sure you write down everything about it.
I get daydreaming about wonderful things happening to you. I do this too and it is a big pain because it makes life seem dull. But what I do to fix that is I have at least five or six stories floating around my mind that I can call on whenever I'm in a slump or start making my life bigger than it is.
I have no clue if this will help, but maybe try meditation? Yoga too, but look into meditation.
Go to a doctor. An adult is good too, but a doctor is probably better. They will probably know a lot more about this. Tell them everything, don't hold back. Something i've learned is holding back just makes life harder.
Okay, I don't know what you are going through. At all. I've never even heard of this sort of thing. But maybe you're being too hard on yourself? I might be wrong and so I won't go into the subject, but think about it.
And lastly, I want to tell you 1. Don't freak out. I don't know if what I've said will help you, but things always get better. Sometimes it takes a while for people to see that, but they always get better. and 2. NEVER forget that there are people in the world that love you for who you are. And NEVER stop loving yourself. That, as much as anything, I believe is stronger than all things. Stronger than medicine, stronger than pain, and far stronger than hate. This might seem weird. I don't know. But I hope some of this helps. 

Good luck, my friend. <3