Every patient is different, but I too developed thrombocytopenia 20k after my second booster. Some minor bruising noted but no frank bleeding.
My hematologist contacted the CDC who while not being definitive and did not provide a written response, (by my physician’s report) verbally told the providers that they have reports of such. They gave a risk factor of 1 in 10 million. They reported that of those reported the overwhelming majority returned to normal in months. Mine took about 18 months. Normal >200k, now for about 2 years.
I have even rolled the dice again and have taken last and this years booster without change in platelet count. I did switch manufacturers just out of unscientific caution.
Again, your experience may be different. You might ask your providers to talk directly with the CDC.