sex in early pregnancy

I hope I get some answers off here I'm in very early stages of pregnancy 4/5 weeks and before I found out last week me and my partner had sex after I had a very light pink discharge sort of mucus type after I went to the toilet.  I didn't think anything of it I just thought it might be the start of my period. Last night we had sex and I got the same thing again after but this time I know it's not the start of a period because I'm pregnant. I'm really worried what this can be and why it's happening? Is this normal? Or am I harming the baby or me inside?? If anyone has had this and could message me back I would really appreciate it thank you so much xx