Be careful with crossfit. I've been doing it for a year, and it's fabulous, but if you're at the point where you're screaming, crying, etc., you should probably back off or scale. I recently spent nearly a week in the hospital with rhabdo, because of a failure to do this. It's not fun. As a former division 1 athlete I thought pushing oneself to failure was "no big deal," but after that experience, I think I'll be more careful.
Note, this isn't to say crossfit isn't awesome. I love it, and will probably go back once my blood levels have finished dropping and I get clearance. Also, it isn't just cross fit that folks get this from. It's any super intense activity that uses a lot of eccentric muscle contractions.
Keep up the good work! Just thought I'd give out my little rhabdo PSA, as I had no idea what it was until I got it. lol.