6 week scan and no sac?

Summer

Hi ladies

Im just worried, scared, and really confused. I went to the ER on Saturday, and the doctor checked on my pregnancy even though I was there for other things. My hormone level was 643. And he did an internal ultrasound, they said they didn't see a gestational sac. I wonder though, because my vagina is very long, if they did not put the probe all the way up, this was a male ultrasound tech and I have never had a male ultrasound tech do anything with any of my other pregnancies. he said that I could be miscarrying, or it could be too early to see anything. I understand that pregnancy is tracked by the first day of my last. Period, which was may 18th, but I was very thorough in tracking my ovulation and the days I had sex, and I'm pretty sure, no I'm a hundred percent sure that I wasn't ovulating until the 7th of May. So in that case I can't be 6 weeks gestational growth, technically speaking... this is my 5th pregnancy, I have 3 boys, but I did miss carry this last January, so that's why I'm pretty freaked out. I am not really having any concerning cramping, although I am breastfeeding my youngest still,and i have some cramps throughout the day. it just feels like the basic Growing Pains of my uterus and my body shifting. I am although not very nauseous which is new for me, and I am extremely tired. So I have the normal signs at least so far of being pregnant and it being OK. Has anybody else had this happen? I guess I've never had a scan done this early, and I just want people to be honest with me so that I don't get my hopes up.

I'm supposed to get my hormones recheck tomorrow.