Yes. Go to the doctor for a proper test ASAP. Over the counter tests have a false negative/false positive rate that is much higher than the test your doctor will use.
No you can't be pregnant and still have your period. You can have a light bleed but not a period. As for the whole negative test thing, it could be a false negative.
You can get pregnant a week before your period, the week of your period, and the week after your period, and some pregnancy tests are faulty.
. . . means that you arent pregnant.
nope
Unlikely - the bleeding probably was your period
Having your period means you aren't pregnant
A female can get pregnant at any age after starting her menstrual period.
You are pregnant
Visit you doctor.
If you have had a negative blood test, it is very unlikely that you are pregnant
Pregnancy tests are not 100% accurate, but being that it was negative and you got your period, I'd say you are definitely not pregnant.
If you're on the birth control pill and had a negative pregnancy test, it is not likely you are pregnant.