You are right that getting a degree to make $50k a year is a waste. Believe it or not (and I know at 20 years old it is hard to believe), the process of getting a degree can make you a better person that will stay with you the rest of your life.

Dude, you have ONE CHANCE AT THIS THING CALLED LIFE. Some mistakes can end up costing you for the next 60 years, and not only in your positive net cash flow (although you don't see it now, it CAN really hurt you here as well). Although it doesn't seem possible, it will hurt your own self-image for the rest of your life. Do you really want to think of yourself as someone who couldn't even motivate himself to finish college? Look at the statistics for lifetime earnings for college grads vs. college dropouts. Look at the percentage of the population that graduates college these days - it is pretty high, do you want to be in the percentage that couldn't cut the mustard?

Banking your entire future on poker is a horrible decision. There are too many variables, as you correctly point out, to count on it long term. What happens if you simply get burned out with it?

What I suggest is to grind your way through this semester. The suggestion to get your arse to the library a few hours a day is a very good one. Don't bring a laptop. Don't get on the net there. Sit your ass down at a table and grind it out. Four or five days a week of this at your intelligence level should be enough to get the job done. Psychology is a very interesting subject, I'm quite certain if you give your profs some credit and actually listen, and dig into the text even moderately, you'll find enough there to motivate you - and not only that, you can use much of it in your poker life.

Beyond that, I strongly suggest you take a step back and think about what interests you. Don't major in something for money. Don't major in something because it is easy. Major in something because it interests you. I faced motivation problems my entire undergrad and law school career. Undergrad, I finally found philosophy and literature after several majors, and I was hooked. I eventually ended up with an English Lit degree. Reading the great philosophers and authors changed my life forever, and although I had my share of bad profs, a few of my classes were worth the entire price of my education, and all the hours dedicated to it.

Law school was a whole new challenge. Only the truly bizarre student (with all due respect if there are any around here) find the study of law interesting. It is horribly drab and devoid of much thought. So, the old key I had found to motivation was gone. Still, I grinded it out my first year and ended up in great shape for a great job. Landed it after my second year of school and seriously coasted my third year. Took the great job, hated it but again grinded for a couple years (after the grind of the bar exam once again studying something devoid of any independent thought whatsoever), then left to form my own firm practicing in an area of law that interests me on my own schedule. In short, the grind paid off in a big way.

I hope this is of some help. Talk to as many people about your problem as you can. Not just your parents, but also friends and maybe a school counselor or two. More than anything, I think you HAVE to grind out some good grades this semester and then reevaluate at that point.