Post-surgery- Day 3

So my ACL reconstruction surgery was on Tuesday, and I was feeling extremely lucky about how it went until about midnight last night. My anesthesiologist had given me the most amazing pain killer/nerve block/shot thing that was supposed to last anywhere from 12 to 48 hours. I thought that it had already worn off and that the pain wasn't going to be too bad. Then last night when the shot actually wore off I realized that I was going to have to deal with excruciating pain. This is hands-down the worst pain I've ever felt. It's like a constant throbbing, stabbing, burning pain. Not to mention that I have an immobilizer on, so it's just extremely awkward to have your leg straight and elevated at all times. The pain killers are doing absolutely nothing for me except making me pass out every few hours. I have no appetite. IT'S ONLY DAY 3! Seriously, how long will I have to deal with this pain?