I used to get strep as well. Had it a couple of times. Never went to a hospital for it, but had it. Here's one possibility -- the antibiotics. While they do get rid of the infection, they also adversely affect the beneficial organisms that keep you from getting sick in the first place. The more you have to take them, the harder it is for your body to replenish those organisms, and chronic illness often arises this way. We get sick where we're weak. And when we're weak. Meaning, when our immune systems are not at their peak. Lots of people get cancer, for example, but in all sorts of different places in the body. It attacks where we're weakest. Keeping a strong immune system as best as you can is the first defense. So even if you're around somebody or some place that keeps giving it to you, nobody else you know is getting it, right? So ask yourself, what in your life might be weakening your immune system? Your diet? lack of movement? Lack of sleep? You get the drift. Because every time you take those antibiotics, you're further weakening your entire immune system in order to fight this, and if you had a strong one, even if you were exposed you'd be much less likely to get it. Who is dying the most from covid? Those with underlying conditions that have weakened their defenses. Can't help you in where you're getting it, but again, if you can get stronger the exposure might not get you anymore. As to finding out where you're getting it, you'd need to do what's done with covid -- contact trace, research where you've been, etc. and see if there's a cluster somewhere in your life.
That's rough. We've had strep throat in our house and man, that hurts like a mother' f'er. There ARE carriers, not sure why your doctor laughed at that idea. But you likely also have a weakened immune system to be so susceptible. What about giving your system a boost? Do you get other illnesses easily as well?