pregancy test questions....

I have the most confusing questions and have no idea what's going on. I thought I had a period 6/1-6/4 I took two tests 6/14 both positive. sex that I would have conceived would have been 5/18 (yes 5/18) and I remember we aren't trying to conceive. 6/14 were two positives then 6/17 I had a negative then I went to the health department that day and got another barely line positive... and I have had 3negatives since. I'm confused.. someone help.