I don’t know if THIS treatment program is the right one for you, but yes you should go to *A* treatment program.
Addiction is a pernicious, incredibly difficult thing to deal with, and ADHD makes it even harder. This stuff about “I should be strong enough to do it myself” is your brain playing tricks on you. Needing people around you to help and support is not weakness, it’s good strategy. You don’t go in to fight the Big Bad solo – you need your Badass Brigade to have your back.
It’s worth a call to see if the program can work with your school committments. An even more likely path would be to talk to your academic advisor and see what the process is for taking a medical leave of absence or getting extensions on your work.
Students encounter health problems ALL THE TIME, whether it’s major depression, or cancer, or getting hit by a car, or substance issues. Schools have policies and plans in place to help students take the time they need for medical treatment without completely derailing their education.
You are having a health issue. You may need to take some time for treatment. There’s no shame in that, and it’s not abnormal or weird. If you don’t want to disclose all the details of your situation, your advisor SHOULD be able to help you find accommodations and workarounds without knowing exactly what the problem is. (There’s always the chance they are a jerk, but most are not).
You should be able to say, “I am dealing with a health issue, and I need to schedule treatments on these days/times for this long. I may wind up missing some classes or have trouble keeping up with my work. What can we do to work this out?”
Best of luck to you. Hang in there!