Your reservations are pretty much the same reservations we all have when we walk into our first AA meeting. But at some point, like you are at now, the pain becomes great enough that we are willing to do what ever it takes to get better. You are doing exactly what you need to do, getting a sponsor and following ALL of their advice. You may not understand why you should do what they will ask of you but at this point that's all you need to do. Just do your best to do all the things they ask and over time it will make sense. Like they say, your best thinking is what got you to this point so why not trust someone else's thinking for awhile.
Believe me, I thought the Big Book was goofy, a sponsor was just some ass on a power trip who wanted to boss me around and there was not way I was going to do ANY of those stupid steps that make no sense at all! After a year of thinking like that and only going to meetings, but drinking, the pain finally got great enough and I said I give up. I then asked my sponsor what to do, he gave me some direction and I did everything he asked of me without question. Finally after doing steps 4 and 5 I felt a great relief and I was on track to living again. Now, all those things I thought were pointless all make sense. I really hope for you that this is your breaking point and you will take all the steps you need in order to feel free and live a great life!