What is causing my sudden sun sensitivity?

[Abbey77]

Hi! I've always had pale skin which burned easily, but in the past I was able to get by with just using sunblock. But this past summer my skin was extremely sensitive and I'm not sure what's causing this. I went on vacation and every time I was in the sun I applied spf 50 waterproof sunblock, and diligently reapplied after going in the water and every two hours. But I still had a horrible reaction to the sun. My skin got red and hot and it was very painful. And it wasn't all over, like a normal sunburn. My skin would only get irritated where my skin touched my clothing or made contact with anything. So after changing out of my swimsuit, anywhere that my shirt or shorts touched my skin it would become inflamed. Or if I sat in a chair, anywhere that my back or legs touched would become inflamed. I have never had this problem before, and it ended up ruining my vacation.

I have searched online and cannot find anything that explains these symptoms. And I've had sunburns before and this doesn't feel like a normal sunburn. The only things that have changed in the last year are that I started taking levothyroxine for my hypothyroidism, vitamins b12 and d because I was deficient, and I started using the nuvaring. Any advice??