Hi Holly,
I don't have MS but have CRPS/RSD (Complex Regional Pain Syndrome) that has lots of the same symptoms as MS.
I was out in the sun yesterday with my mum as we went to the zoo and am paying for it today. I have had to miss school again as I am in a pain flare and think it is because of either the sun yesterday or the fact I overdid it too much. I also have some knee problem that isn't helping with things.
For me, I tend to find that if I have had too much sun, my symptoms get worse. If I am too hot, I also tend to faint from overheating.
My nanan had Progressive MS and she found that the sun bothered her also.
Sorry you aren't feeling well - I hope you feel better soon!