I too have anxiety when it comes to school. I keep having this nagging thought that "I'm not smart enough and I should drop out and save myself time and money". Could the delaying of your schoolwork be related to anxieties about having to go out and get a job? I know I had worries about going out to the "real world" (I guess that's why I'm back in graduate school...).
As for advice, I would say first go see the school counseling service if your school offers one. Ask about possible anxiety/stress related group meetings held on campus. You could also talk to your department adviser about your coursework. My biggest regret in my undergrad years is not using the resources made available to me. There's a lot of people on campus whose job is to help you out, so don't be afraid to seek them out. Good luck!