I strongly recommend LZ drive your car to garage and let professional to find out what's wrong with your car. Let them fix it (like Onion) then you have peace of mind (probably with warranty on work).
If your car is a used car (2nd hand), there is a possibility that the car was not maintained well by previous owner (or bad driving habit).
Since you haven't changed your alternator, then there is a very highly likelihood that it is alternator problem, it has reached its final days and needs replacement. (Ten years is not bad indeed....)
Changing an alternator (after market/rebuilt/used) plus labor should not exceed 250 CAD. That gives you another ten years of peace of mind.
多谢各位的热心回复, 我这就找车行看看。问个弱智的问题:什么是alternator?