Getting a bone graft done tomorrow...

I saw the periodontist recently and it seems I've had a lot of bone loss due to genetics and pregnancy so I'm going in tomorrow for a bone graft. My OB has obviously approved the surgery (presumably due to the risk of infection from periodontal disease spreading to the baby... I'm 29+2) but seemed pretty casual and nonchalant when I talked to him about it. I'm extremely nervous because I don't know anyone who has had this done and have no idea what to expect. I'll only be given local anesthesia so I'll be awake the whole time which makes me even more anxious. Can anyone with experience give me some reassurance?