Antidepressant use and lack of symptoms

Hey guys. So I take lexapro for depression and I'm feeling worried cos I don't feel pregnant at all pretty much. No tiredness, cramping/stretching feeling has stopped a few days ago, nipples (not breasts) only slightly tender, not nauseated at all, mood is perfectly fine ! Jut took another hpt and it's still dark. My beta was 699 at about 4 wk 3 days. I'm now 4 wk 5 days.