Missed period but negative test

My last period was May 22nd, and I still haven’t had my period. I am now 9 days late on my period, and I’ve taken 4 tests and they’ve all turned out negative. What could possibly be going on? I haven’t missed a period in two years and that was due to forgetting to take birth control. I feel like I’m overreacting but concerned something worse is wrong. I know the easy answer is to consult with my doctor and get a check up and I am but my waiting list is forever till now. I do drink alcohol more than I should, I thought maybe the alcohol is causing me to miss my period? Does anyone have any idea?