Hey JR! Boy do I know how you are feeling! The anticipation is really awful!

But please try not to worry. The surgery will go brilliantly and soon you will be healing and getting your life back.
Are you getting knocked out for your op? If so, the surgery itself will be a breeze - you won't remember anything! I was awake for my LIS, but when I got my fistula surgery, I got some happy-sleepy stuff injected into my hand; then I had a vivid dream about being at the helm of the starship enterprise (yes, I’m a trekkie :) ), and woke up with nice nurses checking on me. I didn't have any pain, since they had put a local in my butt, so it was quite numb. The packing was a bit uncomfortable, though, until it came out with the first BM. I got home, took a painkiller (Percocet), which I was told to take before the local wore off. Then I fell asleep. All in all, not a bad surgery experience there. The first few days of recovery can be a bit rough, as you probably already know from the posts on this forum. But, for me, the recovery pain was not nearly as bad as the fissure pain.
The first BM can be pretty scary! But for many of us, it's not nearly as bad as we worry it will be. If you take your stool softeners and eat fissure-friendly food, you should be good to go. Just remember, no straining. Take nice, deep, yoga breaths. Some folks find the first BM can be a bit stubborn. Many of us have a back-up supply of Milk of Magnesia (MOM), just in case the regular stool softener doesn’t quite do the job of getting things moving again.
Also, lots of folks hop in a nice warm bath after the BM to keep the butt clean and stimulate blood flow. You can ask your surgeon if s/he thinks that's a good idea for you too.
If you haven't done this already, you may want to take a quick trip out to gather your recovery supplies. I got the following items:
1. Robaxacet and ibuprofen
2. Miralax (Movicol/Restoralax)
3. MOM
4. Soft, easy to digest food
5. Chemical-free baby wipes (for cleaning)
6. Lots of good movies
I found staying on top of the pain made things easier. I took my Percocets for the first two days, and then switched to a combination of Robaxacet (a muscle relaxant) and ibuprofen. Prescription painkillers constipate, so a good stool softener is absolutely vital. Also, keep up with your fissure-friendly diet and drinking LOTS of water too.
I found it much easier to handle the post-op pain, first because for me it wasn’t nearly as severe as the fissure pain, but secondly because I knew that I was healing and that the pain would subside. Once you’re on the other side of the surgery, it’s easier to cope with pain and discomfort because you know it will improve and you will get your life back.
I definitely understand how scary butt surgery is! But you are going to do great!