Clomid 100 MG

I just finished my second round of clomid on Monday, last month 50 MG and this month was 100 MG. About a week after my first round I started spotting light pink every time we have sex and it's still going on. Were also using preseed because I heard clomid can dry up CM but we have used this many times in the past. Has this happened to anyone else? Or know what could be causing it?