Maybe pregnant

Myra

So I had the depo shot my last day it was finished was last month on the 19th I had ups the day before and then three days in a row after . Now I'm due for my period but I haven't started I took a serum pregnancy test hcg levels are zero but I had ups again last night so y'all think my chances are high of being pg. I'm not trying but I'm not against it I have three kids already but this whole ordeal is very confusing