General TTC

so I have been TTC for 3 months now and it has been unsuccessful. I went to my OB did some tests he said everything is fine, although my period is very irregular . Sometimes I don’t get it for 2 months. I have bought the clear blue advanced ovulation tests. I Have been using it for a month now . I have only ovulated once so far . My question is how long should I wait to see a Fertility specialist ?