The only 2 people on this earth who can come up with the best action plan for you are you and your therapist, together. You WILL need a therapist- you can't do this alone. If you were able to you'd just... be able to. But obviously you can't or you wouldn't be asking for help. You wanted 1 tip to get yourself started on restoring your health? You already did it by asking for help.
You're going to have to get over not wanting to open up to a therapist, or they won't be able to help you. Their job is to help you come to certain realizations and decisions on your own- they can't do that work for you. Only you can do that work for yourself, by being honest about what is/isn't working in your life, what you want to change, what you believe in, what you want more of/less of, what kind of person you want to be, etc.
It's like this: there's a series of rooms with doors you have to unlock and walk through to get to the person you truly want to be, and each door has a different key. You're starting out without any of these keys, without knowing where any of them are. A good therapist will either:
1) Show you where the key is hidden in the room, but you'll still have to go get it, unlock the door and walk through it yourself.
2) Show you that you've had the key this whole time- it's sticking out of your pocket. lol You'll still have to pull the key out of your own pocket, unlock the door and walk through it yourself though.
Sometimes it'll be the therapist who'll have a certain key you need, but you'll still be the one who has to use it to unlock the door and then walk through the door yourself.
When it comes to the drugs, here's what my therapist told me (and he gave a disclaimer that it's an unpopular opinion and that I don't have to agree with it if it feels wrong to me): he told me that drug use in itself isn't a bad thing, and that it's only a problem if it's a problem (I was shocked when I first heard this lol). He asked me what feelings certain drugs gave me and why I wanted to feel those feelings so badly. I told him drugs made me feel happy, got me out of my own head and helped me get through some days when I wanted to kill myself. He asked if there was anything else around at those times that had the same effects as the drugs (like making music or writing, for example), and I answered no. He told me that if I thought about it, doing drugs balanced out my depression and suicidal tendencies, they saved my life during those times and I shouldn't judge myself for instinctively doing something that was making me feel good and basically keeping me from killing myself. He said that in those ways, drugs were useful. He asked me why I then no longer wanted to do drugs, and I answered that they didn't make me feel as happy anymore and had started affecting my health. So in those ways, they weren't helpful anymore (exactly the opposite), and had become a problem. That was my indicator that I needed to bring balance back into my life by doing less (or no) drugs, and more of something else that WOULD make me feel good and get my body healthy again. That's where asking the "what do you want more of/less of in your life" question is important. Balance is important. If drugs never end up causing any imbalance in your life (physically, mentally, emotionally, financially, professionally, socially, legally or otherwise) then no one says you have to stop. All mental illness is to begin with is a chemical imbalance in the brain. Restoring balance to your life could look like going to rehab or therapy, or going on medication, or whatever you and your therapist decide is best. But as always, it's you who's going to have to put in the work, whether that work is taking the medication you've been prescribed, honestly putting your all into rehab and staying clean, being consistent with going to therapy, looking into alternative healing techniques to supplement your therapy, etc.