I know you carry, but for most people, they have a gun at home in case of a break-in. In that situation I have read the average time you have to react is less than a minute, and you might be sound asleep. I don't know how you train for that, plus you are so right that the adrenalin rush and fear is going to make it very difficult to accomplish even a simple task.
It's one reason I like a striker-fired pistol like a Glock or a revolver versus something where you have to manipulate a safety.
You have an advantage at home. You know the layout and most of the times, an intruder does not. Having a gun at home should be a last ditch defense, not a solution to being invaded. Get a good alarm system and a dog. Cameras also help, and put a sign out in the garden or a sticker on the windows in the lower corner that lets a thief know your house is alarm protected. In almost all cases, a thief will choose a house that is an easier target rather than risk entry - and that is the whole point.
I have cameras, a wired alarm system (for fire as well - discount on insurance) and of course, a safe with a biometric lock under my bed. The alarm was triggered once and I had my weapon in less than 20 seconds. The odds of an intruder getting to my bedroom in under 20 seconds is nil. Turned out my son (at the time he was 6) had opened the back patio door in the middle of the night because he said he heard a dog outside or something. We can't own a dog because my wife has allergies.
This is the sign I have in my front garden:
I assure you, a thief doesn't want to go through all the trouble to rob my house when he can get a neighbor with much less grief. An added bonus is that this sign also stops a lot of solicitors.
