First Ultrasound and I've been a mess

Jessica • I have been ttc for over 2 years and we are finally pregnant. I can't wait!
Based on my LMP I was due June 26. Had my first ultrasound and appt. The baby measured 6wks 6 days with a low to faint heart rate. I believe she said 111 bpm. I'm now due 7/6. She said I have a narrow cervix that dips which could be the reason the heartbeat can be difficult to hear because it's so small or i can be less along than i thought. I have irregular periods and I ovulate late according to ovulation sticks. The tech had trouble finding and measuring the baby. I have another Ultrasound in two weeks to check the viability of the heart rate. I been crying but trying to be positive. My doctor said she sees this alot where the first ultrasound the heart beat is low and than two weeks later it is strong. I'm praying it's the case. I'm trying to prepare myself for the worse case scenario but being positive that this baby is going to have a strong heart beat. I cried all night and cry throughout the day. Two weeks feels like forever. I don't know what to feel or think. We tried to concieve for over 2 years, I want this so bad. I just don't know how not to worry. Has anyone had this situation? I pray to God everything turns out alright.