Help please

I started taking clomid 50mg last month. Well went I was suppose to start I didnt I ended up being almost a week late but when I bleed it was all brown and barely any red at all. I'm afraid to test again but I'm supposed to start letrozol today. I have pcos and I take 1500 mg of metformin a day. The crazy part is right before I started bleeding brown I got a very light positive I did test 2 days after I stopped bleeding and I didnt see anything. I'm cramping not to to bad, very gassy, sleepy and very irritable. I need advice.