First, try to locate this page on web and read how others are completely different from you, and they don't care a damn thing about being the way they are.
If possible, can you look for the table in very corner, and you sit with your back turned, so you sort of get out of everybody's sight.
To assure you: I don't think people really pay any attention to others around them sitting and or eating in restaurants, unless you are really handsome and some nice female glues her eyes on you.
If you are going for any talking therapy, ask your wife to go with you in a few times.
Try compensating in some other life areas with your wife, if going out to eat is not your apple.
Do you remember if possibly your father/mother or any relative was harsh on giving you lesson on table manners, back when you'd been young child?
No heart attack will happen unless you shoving the food down your throat uncontrolably.
Pinch a tiny piece by piece of food, just so you are giving it a try and keep a pitcher of water by yourself or some juice. Neither me nor my son nor my mother, can eat without drinking while eating no matter where we are. At the same time, my husband and daughter don't need any liquid. So: keep a glass of something you like next to you: even if it comes down to you, more drinking than eating while out in restaurant. You tried your best to be there first, and comfortable eating will sit one day: sooner or later.
And, for Lorazepam: tappering needs to be really gradual and depend on what mg you were, it might take you six months to get off of it. If you didn't contact your dr. at least acknowledge h/er/im of your decisison of getting of Lorazepam.