11 days late...can i still be pregnant if my blood test came back negative? [took blood test at 10 days late]

Yes you can: But you probably are not. Pregnancy tests can fail in both directions for a number of reasons. They can say positive when you are not pregnant, and negative when you are pregnant. Both are uncommon, but both happen. There are a lot of reasons why your period may be late besides pregnancy. If your concerned, then it is time to call your family doctor.

Very very unlikely: A negative blood test done 10 days after a missed period virtually rules out pregnancy. If you miss the next period, you may wish to get an ultrasound examination. Consult this site. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx