An update (can't believe it's been 10 months!).
I seemed to tolerate the abemaciclib ok at 100mg a day and then 150mg a day and then 200mg a day. Issues arose when I went up to 250mg a day. Diarrhea was AWFUL - kept me awake at night. Was maxing out the gastro stop and had them stashed everywhere (work, car, handbag etc). Couldn't go to gym 'safely' - never knew when it was going to hit. About 6 weeks after my dose increased to 250mg my hair started falling out and by December (3-4 months later) it was falling out like it did during chemo.
My platelets also dropped significantly month on month, so on 01 Jan I reduced my dose to 100mg x 2 times a day - so far so good with no Gastro Stop needed. Had a blood test a few days ago and am currently waiting for a call from the Onc - he said in December it was likely that we would have to reduce my dose.
I don't think I've ever been so miserable - obviously my body was a bit like ''uuuum, no thank you'' Now I need to wait (again) for my hair to grow back. It's only been 14 months since I finished chemo. 2 steps forward, 1 step back - but hey, I'm still here!