I have taken 3 pregnancy test they all came up negative, also my period is 11 days late. Every time I eat something my stomach is having a hard time digesting nothing is settling well. I have not yet had problems vomiting but I have problems with naseua.

Several possible issues, one it may just be a flu or illness and it has your period off. Next at times some women just miss a period or it is a week or two late,

Of course you may be getting a false negative on the test. When was the last time you had sex before your period was due ? You can go to the doctor to be checked, or wait a couple more weeks to see if the period comes and if not try another test then.

I agree with chuck..
Some women's cycle gets thrown off by certain things. If you have has unprotected sex or such you could be pregnant. I had troubles with the at home pregnancy tests at first. It all depends on the hormones that your body gives off.
I'm not dating your pregnant I'm just saying it could be a possibility.
Good luck hope you feel better soon!
~Erica