brakes not working properly

so my car works fine, but i noticed that when i get into my car and try to reverse i will hold the brake and shift into reverse then slowly let the brake goes but i hear this kind of air pressure in the brake then i cannot brake (stop) the car from reversing. i have to push really really hard and it barely slows the car down, luckily it is always out of my driveway or after hours out of work, but then even at that after i switch gears to drive i notice that it goes on its own, like i don't push the gas and it accelerates a little bit. it worries me and no ABS lights or brakes lights are on my dashboard. Help!