Could i be pregnant?

Me and my boyfiend dont see each other much so when we do it usually gets a little frisky. lately ive been feeling very sick. Everytime i stand up i get lightheaded and sometimes loose my vision for a few seconds, ive been having constant pains in my lower stomach area, and their has been a slight discharch in my undies. Could i be pregnant? Any advice/knoledge will help!