HELP please

Sarina • Mommy to a baby boy named Easton wife to a handsome man named john.❤️
HELP PLEASE im 6 months post Partum. In January my period was 18 days late. I ended up having a period feb 9th but it was short.
I didn't get my period all march I'm now 28 days late. I took 3 pregnancy tests last month I got 2 positives then a negative. 
I went to the doctor and they did a hcg test and it was negitive so they gave me some progesterone and some birth control to start my period, but are sending me to the hospital Monday to get an ultrasound he said not to take the medicine till I get my ultrasound?? Is there a chance I'm pregnant 
My husband and I always use condoms but we went twice without one. 
I'm a nervous wreck and want to know what's going on with me.
 My symptoms are fatigue, bloating, headaches.