What Causes Cramping And Fluttering In Belly After Having Unprotected Sex?

hi im getting a clear like discharge thats damping my undies? I had unprotected sex with my bf 5 times this week and been getting little cramps and flutters in my belly almost like i was going to get my period, and also got a really sore thought for 2 days then it went ???? i took a pregnancy test and it says negative helppp xx