Still no period.

So had my little man 6 months ago (he was born at 34+3 due to extremely low waters) and I've not used any contraception since other than condoms. I was due my period 2 weeks ago, 14 days to be exact. Before having Benedict I was irregular, some cycles being 52 days long, well I've taken tests and I'm sure they're negative but got some to take this week just incase I ovulated late and somehow I'm pregnant but should I go to my Drs? It's getting very uncomfortable now and I'm so tired all the time, my moods been up and down and I just don't know what to do?