Clogged toilets are never fun to deal with!
When water starts to overflow in your toilet bowl it means there is a blockage in the toilet or drain line. You will know if the clog is in the drain line if the bathroom sink is also backed up. If other drains in the house are backing up, the problem is likely to be somewhere in the sewer line. The best thing to do in that case is to call a licensed plumber.
Our Plumbers tell us that most toilet clogs are caused by plastic items, sanitary products and small toys. If you can visually see something lodged in your toilet put on some rubber gloves and remove any items. The next step is to try to unclog the toilet using a plunger. Using a plunger works best when the toilet has some water in the bowl, but not full. Place the plunger in the bowl and completely cover the drain opening. With the plunger head under water, press and pump it quickly for 20 seconds. If the toilet unclogs the water should drain to its normal level and stay there.
If the clog persists your best bet is to call a plumbing professional.