sun burn so bad cant put pants on?

So yesterday I was an idiot and went in the tanning bed for 20 minutes without any kind of lotions on, when I got out I felt very little pain only on my stomach, as the day went on the burn seemed to get worst (I have burning on every single part of my body now), it got so bad that I was up all night feeling as if I was going to get sick laying in one position because if i stood up my stomach would hurt extremely bad. This morning I had school and my parents are very strict on me going but I woke up and tried putting on fluffy pants and it stung and I started crying and my stomach started turning again so I told my sister to tell my mom I couldn't even put on pants so there's no way I could go to school and she was very upset with me about it, but it really hurt that bad, the weird thing is it is not THAT red so she had a hard time believing me, I have natrual red hair so I burn easily. Any suggestions as to what is going on??