Periods out of rhythm and no pregnancy

So for almost 4 years I’ve been off the pill and my body has regulated to on time and consistent periods. Since June/July we’ve been trying to conceive. Starting this August, I had a very light period on time then 2 weeks later had extremely heavy bleeding for 2 days which doctor said I could have had a miscarriage really early. Following that episode I got my period 18 days later which was back to normal. Now I am 29 days since my last start date of my period and according to the app I’m 5 days late. pregnancy tests are negative. But I’ve been having some symptoms consistent for the last few weeks. Has this ever happened to anybody? I don’t understand why now that we’re trying to conceive that I’ve started having more problems.