when i flush my toilet it overflows the bowl.?
Answers:
If the onset of this problem is sudden then you most likely have a blockage. Better than a plunger got to a Home Center and buy a Closet Auger. This simply rotates into the toilet and will impel or break up any obstruction. To use it you simply rotate and push down on it until it bottoms out and then you pull the handle back out and this will normally (95%) remove or free any obstruction.
Other answers:
You need to invest in a plunger. Sounds like you have a big turd stuck in the drain.
You need to invest in a plunger. Sounds like you have a big turd stuck in the drain.
Does it only overflow the toilet. If so its plugged. Eat more fiber and use less toilet paper. And buy a plunger or drain auger. If it comes up in your shower and sinks too then you have septic and drain field problems. Call a plumber.