Ultrasound at 5wks, 6 days and heartbeat rate is 78 -worried :-(

[littlebat]

I apoligize if I have double posted this... I am new to the forums.

I'm a couple months shy of 30 and this is my first pregnancy. My cycles have been way off (some 26 days, some 42 days) but I got a positive HPT test on Thursday 7/30 after experiencing a spot or two of implantation bleeding early Tuesday, 7/28.  By my calculations, that would have made me about 6 weeks, 4 days along...? Since I got the positive HPT exactly 3 weeks ago. I went in for an early u/s this morning and the u/s technician told me that I am only 5 wks, 6 days along. She said she could see the fetal pole and the baby's heartbeat rate is 78.
She said she can't tell me anything else - I'll have to wait until my doctor receives the scans from the hospital and calls me (could take a few days).
I've been reading online and I'm now terrified that our baby's heartrate is too low. Anyone else have a low heartrate show up at 5 wks, 6 days? Also, I can't figure out the math of how I could only be 5 wks, 6 days if I got a positive HPT on 7/30. I used ClearBlue digital... maybe it is just super sensitive?
Many Thanks for any info and advice you have!

[littlebat]

Thank you all. Still waiting for the doctor to call to discuss... how nervewracking!

[martikadragoon]

I believe my son's heartbeat was rather slow in the beginning, but sped up and then slowed down again, lol. It started around the 90-110 range, and went up to 160-170's and is now back to the 140's.

It's normal and a part of the development as far as I know.

[JoyRenee]

Well dates can be off by 1-2 weeks because implantation can take up to 12 days after ovulation.

Good luck!

[claire38]

when i had my ultasound that early i had to hold my breath just to see the heart beating and i believe the dr said that hers was low like that too, then i think around week 10 it was in the 170s so give ur little one's heart some time to grow ;)  i am currentl 33 weeks so hang in there the beginning when everything is so unsure is hard but u can do it

[ernie13]

i think the hb starts off much slower and gradually gets faster. i know i went in last week about the same point as you and only saw the yolk sac at 5 weeks 5 days. i went yesterday at 6 weeks 5 days and saw the hb at 120 bpm. are they going to have you go back in for another u/s in a week or so? i meet with my doc right after my u/s, so that stinks you have to wait for the results.
as far as the dating, you could have ovulated a little later, or the egg could have been fertilized later than you thought. its totally normal to be off by 5 days like you are. try not to worry too much. you saw the hb which is a wonderful thing!