Am I ill or is it just my period?

Today I woke up and I had my period so I put a tampon in and got ready for school like normal and about 10 mins before I was meant to leave I needed a poo. I went for a poo and started gagging and feeling sick, I puked in the toilet continuously for 20 mins. I had serious stomach pains after and my legs were shaking. I was really hot so I stripped off in the bathroom but my mum felt me and said I was really cold. I decided to run a bath but still had pain during. When I got out of the bath I was still having cramps but now I felt cold- actually my body temperature was hot. I decided not to go to school (my first day off in 4 years) becuase I felt so ill. I've still got pains now and it's 5 hours since I got in the bath. Am I ill or is it just my period?