I do not think you are being overly sensitive.
I would have come looking for you, even if it were your house, after about 15 minutes...you could have slipped and hit your head on the bathroom counter, had a seizure, etc. I would have at least approached the bathroom and said, "Hey we just wanted to make sure you are ok..." And if you said yes I would have said, "OK, I'll be back in another ___ minutes just to check on you and make sure you don't need anything." It seems like common courtesy besides just your safety, and these are your friends.
Esp. after the two hours, WAY before that I would have come looking for you...I wonder what they think you were doing?? Btw, game or not you were playing, amazing amt of patience.
If you wish to talk to them about it, I might just say, "I was surprised you didn't check on me earlier last night, I might have needed someone to hold my hair back if I was getting sick"...to make a joke about it, but yet inquire as well.
Hugs to you.