in uterus which is not pregnancy symp as u have missed the period one month back only. Naturally 5 weeks pregnancy the fetus will be like a rice grain in size. so that is not pregnancy hence u r having sex
or not does'nt arise in this matter. the clot is either polyp or cyst or fibroid. Nowadays most common thing is having fibroid one in every five women who is having children (more pregnancies in frequent) and the women who aren't having sex or not having childre. Hence u may first take test of biopsy which clearly indicates what type of clot it is. then take medical help for removing that instead of keeping the same till its size rises. Goodluck.