Is there a program that can change passwords in bulk
I sure hope not! Can you imagine what would happen if a bad guy compromised a user's system, then ran that program to change all their passwords to everything?
Have you considered using a real password manager instead of your browser's? That sure would be a much wiser and more secure option. Then you only have to remember the PW to the manager.
FTR, browser based password managers have one big flaw - someone walking up to your computer when you step away can access your accounts on saved sited.
Having a manager also means your passwords are available to you regardless if your browser is running or not, or even if you decide to use a different browser. Note I also use my password manager to store all my credit card information, my kid's Social Security Numbers, neighbor's garage door key code (we traded - for emergencies), bank accounts, insurance numbers and more - stuff I would never want Google or others to know.
There are several free.
Password Safe and
KeePass Password Safe are simple, basic, but very secure password managers.
Enpass,
Last Pass and
RoboForm are very popular favorites too.
I hope you are not using the same password on multiple sites!