My toilet bowl doesn't stay filled. When I flush it acts like it is overflowing then it slowly flushes.. It makes a gurgling sound because the water is so low, almost like it is pulling air down the drain. If I fill the toilet bowl with water it drains out. My other toilet is fine.

It sounds like the Flapper is not seating properly on the bottom of your water tank. I would replace the gasket that the Flapper seats into. Or your problem could be the gasket that is between your water tank and the toilet bowl needs to be replaced.

If I fill the toilet bowl with water it drains out.

Does it do that immediately or does it do that after water is drained from another place such as the shower or the other toilet?

It does it immediately, as soon as I pour water in the toilet bowl it will drain out. I have not seen any connectiong to the shower or sinks. The other toilet operates fine.

You have a crack toilet bowl if the water in the bowl immediately drains away. Replace,no repair.