I had a 5000 unit shot of hcg 14 days ago to trigger release of my eggs. Today I tested negative. How long before I should expect my period to start?

Depends. First recheck the pregnancy test in a few days if no bleeding, you may be using a test with a lower sensitivity. HCG injection isn't a guarentee of ovulation, just increases the chance. If no period by cycle day 35 recheck a pregnancy test and then notify your physician if neg. as you may have not ovulated and you may need provera (medroxyprogesterone).