When to stop??

Hi everyone! I’ve been on clomid monthly since December and still no BFP. Is there a point when it’s doing more harm then good? (I also take progesterone monthly). I’m 4 days late and keep getting a BFN. I’m usually regular within a couple of days. Can this be doing more harm to my cycle than help? I had a miscarriage in Jan of 2017 and have been trying since. I’m starting to feel hopeless. I was supposed to go get an HSG next week but because my period hasn’t come I think I’m going to have to reschedule it. Any input would be appreciated.