I Came On My Period On 4/10/16 For Three Days

I came on my period on 4/10/16 for three days I had unprotected sex with my partner on 14/10/16 then on the 19/10/16 I has light pink blood with clear mucus in my underwear( size of 50pence) the next two days tiny brown strekes, then nothing till today 24/10/16 when I wiped myself there was a bit of red blood- not much.
I have been having like little cramps/ tummp ache feelings? what could be wrong with me