I'm using an online ovulation calculator to track my ovulation, but I'm still not pregnant (5mths). Are they accurate? Any suggestions on other ways?

Seek consultation. If one's menstrual cycles are not regular, unlikely that an online ovulation calendar will be accurate. Probably a good idea to keep a menstrual calendar for a few cycles and if not pregnant, seek consultation with gyn (bring menstrual calendar) for a basic infertility evaluation, which normally would include assessment of ovulatory or anovulatory cycles.