What should I do?

Cycle has always pretty much started on time. however, within this last year it has been all over the place. (comes on it's own time). Earlier this year after 2 years of ttc I had and utopic pregnancy with twins. every since then my cycle has been very punctual, but it is 2 weeks late. I am experiencing extreme and constant nausea, fatigue and a super Sonic smelling abilities. I took a lil .99cents pregnancy test from Dollar tree yesterday. It was negative. What should I do now?