Confused....

So to start Im 23 and have PCOS and hypothyroidism. This is my 4th round of Clomid. On about 18 dpo (cycle day 33) I had a bfn and then that night what I thought was my period.

Normally on Clomid they're very heavy for about 5-6 days. This time it was heavy dark brown for maybe a couple hours then spotted pinkish brown for a day and half. Now im very bloated still and have frequent urination.

Has anyone else experienced this and then later gotten a BFN. I'm going to take a test in a day or two. HELP