This sounds like a whole bunch of L2P. Learn to spot shimmering from Observers or get a Raven.
If the Terran lets you retreat after an EMP, they’re doing it wrong. You pounce when you EMP unless you know you’ll still lose. If Protoss is down anywhere from 1/2 to 1/3rd of their effective health pool, you should be able to easily clean up the Protoss army. Especially when you start layering stuff like EMP with IM. Or cut off the retreat path with mines.
Getting your bio ball stormed sucks. But that’s why you have medivacs and can move out of the AoE, back to the safety of your siege line.