I haven't experienced a sudden mass-resignation in my field, but we have gradually gotten to that point over the past many years through attrition. Healthcare has taken a big hit (hospitals in particular) since the ACA went into place. De facto workforce reductions are commonplace by simply not replacing positions as they are vacated.
In addition, pharmacists in particular are feeling a big pinch. Before the real estate bubble burst in the late 00's, chain pharmacies were opening new stores at an exponential rate - faster than colleges could graduate new pharmacists. This led to a glut of new colleges offering pharmacy programs (a 70% increase over the last 20 years or so). The big chains stopped opening new stores about 10-15 years ago and moved to expansion by taking over local and regional pharmacy chains. This led to a net closure of stores as redundant locations get closed after acquisitions.
At the same time, the new colleges starting graduating new pharmacists at an accelerating rate. These new pharmacists often don't possess the skills that new grads once had. Pharmacy programs were highly competitive 20-30 years ago, but the newer schools accept anyone with a 4 year BS, and put them through an accelerated Pharm D program run by inexperienced professors. For comparison, my alma mater has a 94% pass rate on the pharmacy boards, while the two newer schools in New England have pass rates of 72% and 57%. So we have a glut of lower-quality grads competing for fewer jobs. Salaries for new grads are about 2/3 what it was compared to 12 years ago, and even the better candidates sometimes need a year or two to find a job after they graduate.
I enjoy what I do, and it is fulfilling work, but I got into this field at the perfect time. I am lucky to be working in a hospital now rather than retail, even though we are constantly being forced to do more and more with less and less help. I would never let my kid go into pharmacy now. It is just too much school for not enough pay, if you can even find work.