About to pass out.

I was in the shower and hot water was running and half way through it, I started to feel very tired and weak. I had to kneel down for a minute and then finish the shower and my neck and arms started hurting and I couldn't put as much pressure on my body to wash it. I wanted to get out of there as soon as I could. I was holding on to the railing in my shower and I stood there for a second feeling like I was going to pass out. I never did but I was so close to doing so. About 3 minutes after getting out I was fine. I've never experienced this before. Has anyone else had this happen to them?? Ps- I'm not pregnant.