It's VERY possible that you have fleas in your apartment. Fleas are especially bad about biting you on the ankles. They were already in your apartment when you moved in.
If you've got fleas, then the fleas and their eggs are EVERYWHERE - in the carpet, in the drapes, in the furniture, and probably in your mattress by now.. About every 3 days, a new crop of 100's of eggs is going to hatch out and begin feeding (on you) and laying more eggs.
In order to get rid of fleas, not only do you have to kill the mature fleas, you also have to kill all their eggs. It's going to take more than "hoovering" to do that - you're going to need a professional exterminator.