please read! losing my mind 😩

Quick backstory: had a successful IUI in August. Got BFP at 11dpiui and confirmed with blood work September 8, hcg came back at 80. Followed up 2 days later, it was up to 206. Everything looked great. Had ultrasound a week later, hcg was up to 2200ish (still great) embryo implanted too high to the right. Possible cornual pregnancy. I was ridiculously stressed, but made it to the next ultrasound 3 days later. Hcg was 6,640 (they said this was good) ultrasound still was not looking great. Waited three more days, finally the ultrasound seemed to indicate growth in the right direction, saw fetal pole and saw but could not hear heartbeat- measured 5w6d and seemingly on target. Now here is where I start to really lose my mind. Blood work comes back and hcg dropped! Went down to 6,400 in three days. They told me to prepare to miscarry and come back in four days. That put me at my ultrasound this morning. I go in, it was a very difficult ultrasound (I have a tilted uterus and the embryo is implanted too high still) my bladder would not empty enough for my tilted uterus to cooperate. However, my doctor spent a lot of time with me and after about 15 minutes of really trying his best to get a good view, said, "this was a very tough ultrasound, gestational sac seems to measure at 6w2d (good) but I cannot find a heartbeat today, I can barely see the fetal pole and cannot measure the growth I expected to see, pending hcg results, I am not sure this is viable." Of course I am a mess but accept it and go home to wait to get the call with my hcg results that should be lower than 6,400 to confirm miscarriage so I can get on with the d&c. Well my nurse calls and says my hcg skyrocketed to 26,000! She said to still expect to miscarry, that the increase is normal in miscarriage. My doctor called an hour later to say she doesn't think I'm out yet because of how significant the increase was- and to come back in two days to do another ultrasound internally and externally to force a crystal clear picture of whatever is happening in me. I'm sure you can imagine how my husband and I are feeling right now! I know this was very very long but I really cannot handle the stress and overwhelming sadness of the last two weeks. I understand hcg dropping means miscarriage is going to happen. But has anyone ever had such a dramatic increase after a tiny drop? If I hadn't had the drop I would be perfectly on target for how far along I should be. I'm desperate for any scrap of information or personal stories of such back and forth news so early on. I'm not finding much of anything here or google. I should measure at 6w5/6d Wednesday if the pregnancy were viable. I've been trying for almost three years. If you stuck around through this mess of a post, thank you ❤️