It could defiantly be anxiety. About three years ago I had a span of about two months my legs ached and felt weird like I couldn't walk across room at times. I took magnesium and vitamin d supplements and it eventually went away. I stopped the vitamins but the leg problems didn't return. I think it was anxiety mostly. The hot spells could be anxiety related also.
This is a classic case of a low-grade constant panic. Your heart races and you hyperventlilate, causing you more of the same, thus the tingly legs and arms. To prevent this, sit quietly, and concentrate on breathing normally. This brings your heart rate down, giving it time to send blood to your legs and arms, so no tingle. I get the sense that the Lorazepamisn't doing the job you need it to. Lorazepam is only effective in the system for four hours, that is why you can take it as need. Maybe a bit more often, at your discretion, would be more helpful. Just remember that Lorazepam is a benzodiazepine, and these cause tolerance and addiction in all people who take it. You are on a low enough dose to not worry about this. But it is a good thing to remember.