When did you know it was time to see a fertility doctor?

Hello ladies, I’m new to this. I’m 30 years old and have been TTC for about 8 months now. I’m beginning to get discouraged because i feel i have been doing everything right (ovulation test, sex on and before ovulation days, checking BBT, and testing 12-14 dpo after) however. I keep getting negative test. Is it time to see a fertility doctor?