AF today and feeling depressed

I want to cry right now. I really thought being a whole week late I would get my BFP soon, but it didn't happen. I feel terrible and worried. I have regrets about not seeing my doctor earlier when I knew I had a thyroid problem, she wanted me to redo a blood test and I kept forgetting to fast so I put it off. Now I'm wondering if it's my thyroid fault. I know I can't blame myself, but TTC is such a stressful experience...I feel awful. I wish I had the optimism of many of you here who try month after month with positivity.