Preparing for a FET

I started estrogen patches on March 9 and my retrieval was supposed to be March 29. I went in for a scan to check my uterine lining this past Monday and I was told my uterine is 6mm thick. I’m going for another ultrasound and blood test on Friday to see how things are going. I’m super nervous about that appointment, what are the chances of the lining thickening up okay to proceed with the transfer this cycle? My doctor seems positive but I’m really worried that it won’t happen this cycle. I would love to hear what you guys think and if you guys were in a similar situation how it turned out for you?