Hey... I need help

I am in summer holiday and decided to start going to the gym and the pool for some serious overdue tanning.

After 2 days I found tiny small red dots on my upper arms and they started itching like crazy, I guessed it'll go away, after another day of the same routine I found the rash spread and is now huge rashes on my legs top to bottom, arms, behind the ears, my chest and stomach... it itches and I have no idea what is happening...
For my sake I hope I don't die lol... someone help please.

Calamine lotion or Benedryl may help. If it continues though, you might want to visit the Dermatologist.