I had the same dreams upto 1.5 years after leaving tech. I had them in semesters I didn't even have classes. The dream usually involved me forgetting to show up for a lab course every week, and then I had to do all the experiments during finals.

It's either residual tech-stress or lawschool-stress. Either way, it eventually fades. I think mine stopped after I told someone about them, so that might happen for you now.