TTC w/ irregular period

My husband and I have been TTC for about 4 months now. I have had irregular periods my entire life, even going 6 months without having one. I have been trying the tracking apps without much luck. If I do have "pregnancy symptoms" I don't even know if I am getting false negatives because I'm testing too soon because I don't know how many days I would be passed a "missed period". Has anyone with a similar situation successfully conceived? If so, what did you do?