Hello Marne. I have had many removed from different areas.
Firstly I can promise you that by this time tomorrow you'll wonder what you stressed so much over. The build up is far worse than the actual procedure.
I've only ever had mine taken off at a hospital, though I know some GP surgeries do them too. So, from my experiences......
You'll likely get to wear a fetching hospital gown & you will be asked to lay down on your front. The worst bit is the local anaesthetic- it can sting but it's not agony. You may have 3 or 4 little jabs to ensure everything is numbed up. This bit will last at most a minute.
They will check you are numb before starting. You will see nothing & hear very little. The surgeon or nurse will likely chat away to you & you will find yourself relaxing & not really focusing on what is going on.
The op itself, assuming the removal is pretty straightforward will likely take 10 mins max. You'll have a few stitches put in which will come out about 7-10 days later (that sounds much worse than it is too!) & a dressing will be applied. You may be instructed not to get it wet for a few days.
You may feel a bit uncomfortable once the anaesthetic wears off- sore but not excruciating. Nothing that a couple of ibruprofen or similar won't address. Also, as it heals it's very common for the scar to feel really itchy- again, nothing to worry about- it's all the nerve endings & skin knitting back together.
I'm not sure of the reasons for the removal of the mole, but it will be sent off for analysis anyway & the results passed on to you at a follow up or perhaps when the stitches come out.
Feel free to PM me if you have a specific question, but honestly, it really is nowhere near as bad as you are currently envisaging.
Wishing you all the best for tomorrow.