Now that you've had a chance to vent (and boy, do I understand that need, sometimes!) it's time to get to reality.
I agree that it sounds like your mom is passive-aggressively expressing her worry about you having this surgery, and that's understandable - hey, all surgeries have risks and those risks are the FIRST and LAST things that moms think about - including my mom, and I'm more than 50 years old
If you do have the surgery on May 2nd, did I understand correctly that your mom won't be out of town until the 7th? If so, it's all golden, and she'll have the chance to see that you're okay, AND you will have your ride home. By the way, that is pretty normal procedure - you'll be a matter of a day or so since having anesthesia, and you'll probably have had at least some pain meds. You won't be at your best cognitively because of it, and your ability to respond to things quickly will be reduced so they want to make sure you get home safely. However, you will likely be just fine on your own most of the time. As others have already said, you'll be doing very little but sipping and walking around the place for a few days.
I get that your mom is making the schedule tough, but you have to remember that ultimately you're expecting a favor from her - family or not, she ALSO has a life and isn't at your beck and call, any more than your schedule should revolve around her. If you want her help, then it's right to accommodate where you can. If the schedule HAS to change because of insurance, move it out one additional week - I know you don't want to wait - heck, I'm not happy about waiting until late July, but the alternative is not good for my husband or me, so I'm sucking it up (and I've been planning this since last summer, too!). It's a compromise you can make that isn't a HUGE thing when you think about it logically. The alternative is talk to the hospital and arrange for late discharge, tell them you can't have an escort home until after 5 PM or whatever and ask what they can do. The likelihood is that there is something they can do if it's a question of a few hours. Then get a friend to come and get you after work.
Hang in there, it will all work out. Just take a deep breath and don't panic. There ARE options, you just have to think it through.
Best of luck!