Can Taking Anti-depressant At The Time Of Conception Be Harmful?

I think that I could be pregnant, I am a few days late on my period and having horrible mood swings and other symptoms but I am getting a negative test. I also stopped taking my low dose anti depressant because I was scared if I got pregnant it would effect the baby. I have stopped them before and did not react like this so I am wondering could the mood swings be from stopping my medicine or could I be pregnant and not getting a positive?