Felling horrible

Ximena
Hi all , I am 6 weeks along yesterday went to the doctor and end up having urinary infection, she did first ultrasound and saw the sac and yolk bag. 
There was some beat but it was quite slow, she said not sure if its baby or is the uterus and sac beat, something like that. Then she found i also have a quiste in the ovary, which she said nothing can be done about it while i am pregnant. 
Yesterday night i started bleeding more than usual, but nothing much, i have been spotting pink so far, and this morning i wake up to a little more bleading, and i have a lot of stomach cramps, i am not sure if its of the urinary infection or the uterus i am scared as shit, is anyone else been though something similiar, or at leasr anyone bleed after intravaginal ultrasound?