I'm in the exact same boat. However, I deal with depression as well. So it's an ADHD/anxiety/depression three-way.

I am currently in a similar situation as you. Life went to shit after college. Was undiagnosed for years, never talked to anyone about my problems. I would end up lying to my friends and family about my academic performance.

Three times I came close to coming clean. The first was whenever I first started having problems. I failed an entire semester. I was devastated. I was allowed to continue at school, but I lied to my parents about my performance. Nothing had changed so I continued to perform poorly and resulted in being dismissed from the university.

After being dismissed I took steps to fix myself. I knew something was wrong. Started seeing a psychologist and talking with my doctor, got diagnosed, and on medication. The only issue was that I was lying to my psychologist because they wanted me to do things that I wasn't comfortable with (namely coming clean to my parents). I ended up coming back and initially doing great. Got straight A's my first semester back. The second semester, however, it was back to old ways. I did decent in half of my classes, but not the others. This demoralized me completely and I was prepared to leave again.

Because I had done well my first semester back, they allowed for me to stay. Again, still lying to parents and friends about my performance, making up excuses along the way. I was pretty beat down at this point. Fell out of a structured routine, got depressed again, ended up failing classes again. Three strikes, you're out.

This leads me to my present dilemma - fixing some of the damage done. The chickens have come home to roost. It's time for me to fess up to my parents - finally. I'm out of tricks. I never meant to hurt anyone, though. I tried to direct all damage towards myself. However, all of the stress and pressure proved to be too much.

This entire time I've been trying to juggle a lot of shit. The gigantic lie that I've built around myself to looks successful to my parents/family. Drug abuse which has seriously hindered my life. Struggling with a one-sided relationship that I can't seem to let go of. Worrying how my parents will react to this (they're old and have been through a lot, I was their favorite child). Just feeling like I'm constantly swimming, trying to stay above water. It sucks. Big time. I feel like I can't be productive in this environment.

So, this is the week I have to tell them. Like you, I'm being forced by outside factors. I have less than a week to organize everything for when I tell them. I know that they will forgive me, as it's just the people that they are. I'm just disappointed in myself for letting them down. I never wanted my life to be this way, I was just kind of steered this way by myself. This is definitely going to damage my trustworthiness, but I'd rather build myself back up into something respectable than to keep living under the stress of a lie. It's been almost 2 and a half years.

Like you, I wonder about how much of my disease is to blame. I feel only partly. You have to take responsibility for your actions. It sucks in the moment, but it will all be just a distant memory eventually.

Change is scary. Letting people down is depressing and scary. But you will get through it, and you will move on. People will trust you again. It just takes time. As long as you are honest about where you are, where you want to go, and stick to it, you will be fine. Trust will come back with time. Life can't always be sunshine and rainbows, you have to go through obstacles and shit times. This will be a shit time, but you will feel better in the long run. Just get it all out in the open. Believe me, I'm not in a good place right now. I have to do this very soon, and I'm not looking forward to it. But I know that my parents and family love me unconditionally (I hope you are in a similar situation). While it may take some time to rebuild our relationship, it's worth it in the long run. The sooner you start working on it, the sooner this whole thing will be behind you.

Just remember to take your medicine, be persistent with your goals, and keep to a schedule.

A tip: Try writing a heart-felt letter instead of doing it face to face. It gives them time to mull over what you're saying. Explain where you're coming from, acknowledge your mishaps, demonstrate how you plan to fix them, and then follow through.