1st bad trip

last night i experinced my first bad trip. at first it was going great and then something happened. i don't know how thought. everything was perfect the setting, the people. i only ate a half a bag and have been trippin' for the past couple years. i went outside in -10 wind chill with a t-shirt and socks and thougth it felt good. i was just dripping wet with sweat and could hear a hospital room in my head, but i wasn't there. i'm just confused as to why this happened. if anyone could let me know i would be a lot of help.