Normally docile snake being bitey

He's taking full grown mice, but they aren't leaving much of a bulge in his stomach. He's been fed three times this week to compensate for the fact that he refused to eat for a couple months.

Oh, when you said he was 3 years old I just thought you raised him up. Ok. Where he rubs his face on the climbing branch do you see any injury? Does he have any mites or scale irregularities that you can see or tell. These are a few things that can irritate the animal. The main thing is to leave him in the enclosure and wait to get more clues as to why his behavior drastically changed.

No, nothing on his face looks wrong, he looks the same as always.

Yeah, I see some other members have some thoughts on it. We will get to the bottom of it soon. I mean we're checking all the bases. For now just go in to clean , change water , and to feed. Don't handle him at all for now.

I'm glad to have so many people trying to help me with this. He's my first snake, so it has me very concerned, as I've been trying to do everything right.

If he's a three year old male he may just be super hungry now that he's stopped fasting; even an XL mouse isn't a decent-sized meal for an adult ball python. How much does he weight? And have you tried him on rats?

He just ate now, and I'm unsure of how much he weighs. I haven't been able to get a scale to weigh him. I'll try feeding him a rat next time, I'm just worried it'll be too big for him with how skinny he's gotten.

Even after being fed yesterday, he still seems very, very irritable. I'm unable to pick him up due to the fact that I KNOW he will bite me at the moment.

You shouldn't be handling for 48 hours after feeding anyway. Weighing is usually done just after a bowel movement so as to get an "empty weight".

Could his eye caps from previous shed still be there? If so, he can't see well and the more food he gets, the more he think's you could be food, until he bites.
And would it be possible to set up another enclosure? I have heard of some snakes that think that if their hungry and there enclosure opens, they could think that it's food not your hand, so people suggest feeding them somewhere else from their actual enclosure- although i have never had this issue so i do not know if it works. Especially if he is also striking when he is outside of his enclosure.
Generally I don't wait 48 hrs after feeding my snakes, I wait till the next day and they are fine, they haven't bit me so far