Do consider taking less of a load while you are working if the grade is important. Two reasons. It would be easer to take a classroom class while working and you could devote more time to the study. I've forgotten the actual numbers but per credit you are supposed to spend about 3-4 hours a week studying. So if you have 2 classes of 4-5 credits thats 12-20 hours of study time on top of your full time work. When I went to the U of M back in the days when a student could actually work and pay for a 4 year degree I had a job that allowed me to study at work about 3-4 hours. That and my great memory back then got me though, but if you have ADD, you are going to need that time for retention.
Don't just give up. It hard when you just want it all over with all ready, but even a bit at a time will get you there, give it up and you won't get there at all. People with college degree make a lot more money in the long run, so stick with it. If you have any idea at all of which 4 year you want to switch to get together with a counselor and do some long range class planing to make sure all the classes you take will transfer to there. There are some classes that are more trasferable than others, the counselors should have a list. Best of luck.