I have allergic reaction to a bee or wasp sting

I am an outdoors kind of guy. Every couple of years I can count on getting stung by some sort of wasp, bee, or yellow jacket. When I get stung I experience a burning sensation that only lasts for 10-15 minutes. That's it. After that it's as if I were never stung. Well not so this year. A month ago I was dressed in  shorts and boots without socks  while mowing the yard. I passed the mower over a nest of ground bees or hornets. Well, they got riled up and I think I got 3 stings, 2 for sure, just above the boot line on my lower leg. The stinging & burning was more pronounced than I usually experience.  The burning sensation didn't got away for many hours and when it did t was replaced with intense itching and a lot of redness. About week later all was fine.

This is a photo I snapped a few years ago of a hornet that stung me while I was driving down the road. He must have come in a window & got lodged between the drivers seat & my back.

Another week pass by and this time I  pulling weeds in the garden and lo & behold, there was another nest of in ground bees. Sure enough I got stung on the calf of my right leg. Well, just as before this was burning and itching and seemed more intense than the earlier stings.
Maybe less than 2 weeks go by and I am sitting peacefully in a chair when out of nowhere I feel a sting in my right shoulder, close to the arm pit. Well, my reaction to that sting was far more severe. My arm became inflamed from the shoulder to the wrist, red and hot. The next day it began to itch intensely and blisters formed on the skin. So I went urgent care. They prescribed some prednisone and after 3 days the itch was almost all gone. It turns out that the effects of bee stings is cumulative, each successive sting build upon the previous stings thereby manifesting in more intense reaction. I am now guarding against any more bee encounters for this season. I would hate to see how I react to one more!