Have been having spotting for almost 4 weeks now. Initially it was brown, the past couple of days it has been red. The frequency of spotting has also increased. Initially it was once a week and now it's almost every alternate day. What could be the problem? 3 pregnancy tests came negative: 3,4 & 5 weeks after non penetrative sex - only b external rubbing and no ejaculation. Sex was 6 week ago. Took covishield vaccine around the same day as the first spotting. She has irregular periods and hasn't had one in 3 months now.