Hello I'm new here and I needed some help. I took the Epo shot after I had my second baby in May and…

Hello I'm new here and I needed some help. I took the Epo shot after I had my second baby in May and I was suppose to go back in Sept. to take my second shot but didn't go. After that I've had irregular periods. My first period I got was in Oct 22 and lasted until the 29. Then the next month I had my period twice the beginning and end of the month then in December I was 10 days late according to my period tracker && this month I haven't gotten my period it also says I'm a week late . I've been feeling very nauseas lately for the past couple days some days I feel bloated and other days I don't . Yesterday after having sex (I'm sorry if it's tmi) I felt dizzy and then threw up I'm not sure if I should take a pregnancy test or if it's just my hormones being unbalanced because of the birth control :( I've also been extremely moody I cry over the most random things I can't sleep /: what could be going on ? By the way I took a pregnancy test Monday morning but it came out negative