Hello everyone) I have an unstable cycle, the last two cycles were 27-…

Hello everyone) I have an unstable cycle, the last two cycles were 27-29 days long, on day 8 of the cycle I had unprotected intercourse, it has been 2.5 weeks since then Sensitive breasts, like they're itching all over, nipples hurt, there is a pull in the lower abdomen, but not as strongly as before menstruation, nausea but not in the morning, and this lasts for a short time, cold water helps. In general, I read that on day 8 of the cycle (that is, after two days after menstruation) there is very low probability of conception, until the next menstruation, it takes a long time. Don't know if I should take a test