Would I be considered infertile if I've been ttc for almost 3yrs but I don't have intercourse every other day, I have sex bout 5-6 times a month!?!

Maybe. It depends on the timing. I recomemd you read "taking charge of your fertility" by toni weschler. She explains how to figure out when you are ovulating in detail. If problems persist, see your gyn.
Yes, seek help. As long as you have been having intercourse without protection for more than one year you would be considered infertile. Even at 5-6 times per month over 3 years time you should have come up with a positive test. I would recommend that you see a doctor to evaluate if there is any reason you have not conceived.
Yes. 'infertility' is defined as a couple that has unprotected intercourse without conception for one year. This is based on observational studies demonstrating about 85% of normal couples conceive in that time. This definition does not depend at all on 'actively trying, ' just that a sexually active woman is at risk for becoming pregnant with her partner during that time frame.