Needing some encouragement.

Sally • TTC for baby #2
We've been TTC for 4 with the help of  meds. I've never had a regular cycle and at time I visited my dr I hadn't had a period for about 4 months. Really hard to track ovulation without have a period. So my dr stated me on Clomid and Medrixyprogesterone to help start my period. I went through two cycles using Clomid without ovulating. This past cycle my dr took me off Clomid and put me on Letrozole. This time I did ovulate. AF was due yesterday but since I'm never regular l I don't put much value in when a calendar says it's coming. I've taken two test and gotten two BFN
​I've been crapping (normal I know since AF should be coming) but today I've noticed a light brown discharge when I wipe. I know it's probably early signs of my period. But Im hoping it's implantation bleeding. I'm a realistic person so I know AF is coming. It's just been a long month with more downs than ups. 
​Any words of wisdom would be welcomed.