I felt this during the big injectable estrogen shortage of 2019. Ended up begging an ex for some of their vial because I couldn't get my Rx filled anywhere.
I had the timeline wrong, it was 2016-17 apparently (years have been a blur for me.)
There was (is?) a duopoly of manufacturers for estradiol valerate: Par and Perrigo. [0] Perrigo stopped manufacturing, only disclosing issues with "shortages of an inactive component" to the FDA and refusing further comment. Par said their supplier for the API pulled out, and had to rework their supply chain.
I eventually managed to track down a trans-run compounding pharmacy that had apparently stockpiled the stuff (so grateful to my community!) but it was a rough time and I'm glad my ex came through for me. Detransitioning is harrowing, I speak from experience.
