Could I be depressed? Am I subconsciously self-medicating?

Well, first of all, I'm glad to see that your self aware to the extent of questioning whether or not these behaviors are or could be detrimental to your health. But to get straight to the point, your current reliance on these substances to stay 'in the moment' looks very much like self medication from my point of view. Drugs can be a good occasional stress reliever, and may sometimes be even insightful or theutic, but the drugs you are using (marijuana, ADD medication, nicotine) do not serve those purposes and the frequency of use (every day) shows a beginning reliance on the said substances. I've been there before, and I didn't realize things were going downhill until I hit rock bottom. You also say you would never do 'hard' drugs... I think it's important to mention the fact that the main ingredient in most ADD medications is amphetamine/amphetamine ogues/amphetamine salts, all of which are moderately addictive, and can potentially produce a harsh comedown or depression upon stoppage of use. But I digress. From my own observations, most of the people who fall into addictions or self-medicate have underlying problems in their life relating to familial issues and/or instances of emotional and physical abuse, both of which you mentioned you've experienced. So I think that yes, you are beginning to self-medicate. The course of action you take is yours alone and sometimes it is hard to stop even if you're not blatantly psychologically dependent on the drugs. The bottom line is, that which once could have helped will only serve to complicate the issues you're dealing with already under these conditions. Remember, there are people who care about you even if you don't know it. If you have any more questions, feel free to message me.