TTC after Depo

I need some advice. I took 2 shots of Depo that lasted until September. We have been TTC since then for baby #2 but I haven't gotten my period other than some spotting in September. I know some have been TTC for much longer and I can't imagine how hard it's been but I feel so tired of trying. And the fact that I haven't had my period makes me a little worried since I have always had a regular cycle. I keep ending up with BFNs and the sex isn't even hopeful anymore... I feel so confused about my body. Should I see a doctor? Did the Depo ruin me forever? Advice please?