We have friends visiting us here in Budapest. It’s 39 degrees and they are all in the pool shouting for me to come out, my family included, and enjoy the sun. Clearly can’t, feeling sad that I can’t and that no one gets it 
Hattiesmum I totally understand how you feel! People do not understand what they cannot see. Sometimes I use half truths in these situations such as having a headache or feeling unwell. It won’t help with you wanting to join them but it will take some pressure off of you. Good luck!
I get a visible rash when I am out in the sun so my family and friends get it and understand why I can’t join in on the fun. But unfortunately my rational side does not always win out and I indulge in outside activities and regret it for days afterwards.
I know how this feels. We have a pool and it’s upsetting that I can’t hang in the pool with friends and my kids. We partially solved this dilemna by building a trellis at one end of the pool with the solar heater on top. So there is always some shade for me to sit in. By mid afternoon the deep end has shade from the trellis so I can swim. We’re going to put misters up too so I can stay cool.
Thats a great idea, thanks.