Trying to conceive for months already

I been trying to get pregnant for months now aka 6months and haven’t been able to get pregnant. It’s really hard to know when I’m ovulating because I don’t have a regular period each month. I get my period different days each months and sometimes I won’t even get a period. I’m starting to get so upset and angry at the same time. it’s so heart breaking when I take a pregnant/ovulating test and there both negative. What do I do lady’s?