Dark, red itchy rash

In the past week, I have broken out in a rash, under my breasts. There are large, dark red patches,very itchy and bumpy. This seems to happen every time the weather gets very hot and I have usually broken out under my breasts, on my chest and neck with these horrible,rashy,
itchy patches. Using powder, to keep my skin dry does not help and cortisone skin creams do little good.

I am 49 years old, pre-menopausal, have been very irritable and stressed lately,
can't stand a lot of noise,
loud noise just upsets me,
feel like I am retaining fluid even though I am incontinent, have bad case of insomnia,energy seems low, problems being able to lose weight, am a writer but I seem to have lost creative center, my hair is dry and brittle, been very stressed out by my environment. I prefer iights off rather than on and feel better when things are cool. Have had bouts of occasional depression.Heat seems to make rash and other symptoms worse.

I have cravings mostly for salty, very spicy foods, cheese, poultry,sometimes for sweet things but not as much lately,also crave bitter things like non-alcoholic beer. Prefer cold drinks to hot.

What can I take to get rid of this rash and ease these other problems?

Thank you for your advice.