What should I do???

I'm 15dpo and af is 4 days late. My cycles are ALWAYS 28-30 days and now I'm on day 34. I've been cramping for about a week, I'm nauseous, gassy, and constipated. For the past 2 days my cm has been quite watery, and today its like egg whites.....but I already ovulated 15 days ago AND I'm 4 days late for my period???? Is egg white cm and watery cm a sign off pregnancy? Because I took an ovulation test and it was 100% negative. I took pregnancy tests at 9, 12, and 14 dpo and all 3 were negative. What should I do???