sadness after sex

hey girls, so i just had sex- literally just had sex thirty minutes ago, and it was great and there was consent so i don’t know why i’m feeling the way i do. after finishing, it’s like i completely crashed and i currently feel so low, sad, and empty 😔 this doesn’t happen all of the time to me but it’s happened before. am i alone on this? does anyone else tend to feel this way?