Confused about pregnancy and cycles?

Iis there a possibilty to be pregnant and still have periods. About two months ago i started feeling morning sickness and all the other pregnancy illness but tender . I have been getting my periods but thay have been either late or early and short by a day or two. i still have frequent unriation and my stomach has harden quite a bit. Also i have taken many pregnancy test all have came back negative. so could i be pregnant and what should my next step be.