Fibroid still not gone after hysteroscopic myomectomy

Hello I’m searching Reddit for situations like my own and would love any and all feedback.

backstory: I’m a 33 year old TTC for a year now. had 2 chemicals this year, one in Jan and one in March. In May I had CD 3 labs and US due to a very short luteal phase and heavy periods. The US showed a 1.6cm submucosal fibroid in the posterior region of my uterine cavity. I underwent a hysteroscopic myomectomy and my doctor said she removed 99.9% of the fibroid and shaved it down to the base. she said I started taking in all the fluid and for safety reasons had to stop the surgery but was essentially done by that point anyway. Fast forward we conceived right after in July and it turned into another chemical. My periods post op have also still been very heavy if not heavier than before. I’ve reached out to my doctor and askEd for a sonohystagram and she thinks it’s a good idea. What could be going on here? Could this be retained fibroid that wasn’t fully shaved off or could it have continued to bulge through post op? I’ve just finished my first round of letrozole and now I’m terrified to try again and almost want to wait for a diagnostic work up. I truly cannot imagine another surgery and another recovery period. Any and all advice/feedback is welcome.