Yes. Sometimes the test is negative and there is still an ectopic pregnancy. Here is a website i found that may be helpful to you.
http://www.webmd.com/baby/tc/ectopic-pregnancy-symptoms
hope this helps!
could it be ectopic even if the pregancy tests come back negative
I think that you should schedule an appointment with a gynecologist. If you think there is a possibility that it is an etopic pregnancy, then you need to go to the ER ASAP. If it is an ectopic pregnancy, it could be a life or death situation. They would do a transvaginal ultrasound to see if that is what it is and they would be able to see if it is a cyst at the same time. I think that would be your best bet, as an ectopic pregnancy is nothing to play around with. Please let us know how you are doing and what you find out.