Something other than pregnancy?

Hi I'm 27 with 2 kids and my husband had a successful vasectomy 12 months ago. The last 6 weeks has been very stressful but iv never missed a period unless pregnant. 7 days late, fatigue where I feel low energy no motivation and just want to sleep, depressed where I can't seem to pull out of it, teary easily, gagging with stomach pain on and off through day, no sore boobs though, been really moody, no sign of any blood, cramping everyday where it feels my period is coming but doesn't and 4 negative tests. Any ideas?