So frustrating!!!!

So me and dh have been ttc for a couple months now, but my cycle is so irregular! So I started taking these fertility blend vitamins to see if it'll make my cycle come on(my last period was in April!) but now I feel sick and I kind of feel pregnant. Idk if it's the pills or maybe I'm about to start or what! I've taken several tests and NOTHING!!! And I'm scared to take another one because I know it'll just be negative... I have a 4 year old already and when I got pregnant with him, I conceived in December and my period before then was in October!!! Idk how that is possible but it happened! I wish I could just have a normal cycle so I would know!