Of course you are grieving; the pain from whatever caused the estrangement returns full-strength at a time like this. I hope hindsight helps; having removed yourself from a toxic situation was a sound move and one you need to remember was necessary. (My reference for this is from a similarly toxic relative who caused estrangement in our family - cutting your losses and moving on with your own life is the healthy thing to do. If that relationship is beyond repair you only hurt yourself by leaving yourself open to more harm from them if you keep trying.)

That said, were there early good times with her that you can revisit and celebrate, so you're not throwing your own past away?