Hi. I am so sorry about your baby being sick
I think Pet Plan doesn't exclude pre existing conditions, but you'd have to check there website to make sure. Some pet insurance places won't cover pre-existing conditions even if they don't get discovered until later. You just have to look at a few and see which won't deny you for that.
I'm sorry I couldn't be more helpful!
I hope Bella feels better quickly and that it's nothing serious!!!