Kill me now!

Ok so I started getting back into the fitness/working out thing last week. I really like my gym and I thought I'd try out a bootcamp style group workout that they offer (For FREE) so I went to my first one last night. HOLY CRAP was it hard! I seriously almost died, but it was great about an hour later :D I called Mark on my way home and literally started bawling. I was just toasted. It was core and cardio for an hour, minute and a half sets between core exercises and then we had to run to a machine and go at a set pace for a minute and a half, no resting, 14 stations. It was brutal. Then today I went back for another session from 3-4, except it was upper body instead of core, and same cardio. It was really hard, not quite as bad as yesterday but seriously tough. The cardio kils me, we have to run at a 15 degree incline at a 4.o pace! About 30secs in I'm burnt! Its like the longest minute and a half of my life, repeated 15 times! Its exactly what I need to be doing....So I'm going back tomorrow for Legs/cardio. Help!!!