I'm 5 days late and I had a blood test yesterday to see if I'm pregnant. They said the test was negative and I was wondering what the chances where that it was wrong? I just haven't ever been this late before and I'm trying to get pregnant.

They can be wrong if done too early, but rarely would they be if you are already late for your period. Far more common for a period to be off than for a blood test to be wrong at this stage. Give it another week and see if your period is just late. Try another test at that time if need be.