Here’s what’s going on so far in my pregnancy ...

I was like 5 weeks pregnant when I got a transvaginal u/s done due to some pain I was having the ultrasound tech saw nothing but thickened lining of my uterus no gestational sac absolutely nothing! I was heart broken I thought I wasn’t pregnant and all hope was lost... I knew my dates were right too! Then a couple days later had my hcg levels drawn they were 3,075 and then 72 hours later had another draw and they were 8773 more than doubled so doc said probably not ectopic... im 6 weeks now was it just too early to see my baby’s sac? I have another ultrasound on Friday to see if they see anything ! I’m just wondering if this has happened to anyone else and if so what was the outcome?