Weird feeling

To start off with I've had sex 2 -3 times a month unprotected using pull out method for the past 4 months.I had previously thought I was pregnant due to symptoms I was having but then got my period.I am now feeling nauses at night and feeling bloated all the time. When I walk now I feel like there is weight on my uterus. I have gotten my period every month usually around a week late. Last period was very short but still had it. What do you think is wrong with me ?