If the output has changed significantly then the angle shown (to the strings) I would doubt is responsible. There might be other factors that will impact......like something shorting or being pinched.
Look at wedging something small temporarily in the rout to straighten the pickup - if that indeed is the fix then you will need to look at the pickup feet angle or foam underneath to keep it level.
I notice, a great many stock pickups are louder/higher output than even "high output" aftermarket replacements (Dimarzio or Duncan.) Part of me feels like stock pickups are designed to be very compressed/forgiving/loud, to sound 'better' than whatever they're sitting next to at the store (loudness war.)
Do you remember how it was set before? First step is to get it to the way it was set before. If it was more level, I use the pickup foam like Lew does. Pretty much any foam would work. Start there, and see if it makes a difference. Also, how did the angle change?

it set normally like the other, idk how exactly the angle change, i think it happened when the earthquake appear at my place and my guitar fell (in gig bag).
in this case, does it affect the tone? or the output problem bcus of wiring problem or volume/tone pot (something like that)
What happens when you measure resistance off a guitar cord plugged into the jack? Do you see full or partial DCR?
There is good chance something was damaged when your guitar fell. It could be a volume pot, switch, or the pickup.
Can you do guitar wiring?
If yes, run wires directly from the pickup to the output jack and see how that sounds. If it is full strength you probably have a damaged pot. If it still sounds wrong then the pickup may be damaged but that is unlikely.
Good luck!
maybe i'll fix the angle firstWell, with wiring problems, it usually works or it doesn't. The angle can and will affect the tone, though.
The angle can and will affect the tone, though.