I coughed and threw out my back. Help.

Ow. I am still a bit under the weather due to a nasty cold. Anyway, this morning I was in the bathroom coughing up some green stuff...and the coughs were particularly violent. I threw out my back. I'm having what seems to be muscle spasms in my lower lower back. I don't know what to do. To make things worse, tomorrow is the first official day of practice for the university swim team. I really want to go, and I really want to swim. How do I fix this so I can swim by tomorrow? And should I tell my coach what I did today via e-mail? Will she believe me? Since it's the start of the season, will I even get to stay on the team after this? Help me. Update: I went and saw a Doc at my student care center today. Apparently I have Piriformis Syndrome which is causing sciatica in my left side. 4-6 weeks to heal. Anyone had this before?