As a kid I was quite frail and prompt to being unwell. One cold followed another one, every allergy ended up with a cold and it all resulted in taking another antibiotic. Back in the 80s neither my mum nor even the doctors could see the connection between antibiotics and allergies or recurring colds. Even now my mum's first reaction to a sore throat is an antibiotic! I stopped it when I grew up old enough o say ’no' and now I am against even a simple painkiller but obviously the damage has already been done and now I pay for it with various allergies or infections.
Even now, when we are constantly being told to avoid taking unnecessary drugs and both immunologists and allergists have noted a dramatic increase in the prevalence of allergies linked to antibiotics, I still personally know a lot of people who religiously run to a GP for yet another perscription and wonder why they are constantly off sick.
Your immune system is the greatest defence against foreign invaders on the planet. It’s got its watch on 24/7 and it has the ability to remember harmful agents and how to destroy them. Much of the immune work is done in the intestinal tract. Antibiotics are designed to kill or halt the growth of bacteria. They don't target your white blood cells that we normally consider our immune system but the bacterial cells, which is a completely different thing.
The difficulty is that antibiotics do not differentiate between "good" bacteria and "bad" bacteria, thus hey just kill all of them. The good bacteria living in your digestive tract helps to fight off bad bacteria, aids in digestion, nutrient absorption, and keeps yeast in its proper balance. The absence of "good" bacteria in your gut leaves you vulnerable to repopulation or mutation by "bad" bacteria, which can cause some serious problems and having the same allergy or cold coming back within a month. This is why you'll often be told to eat some yogurt when taking antibiotics, because it'll repopulate your gut with "good" bacteria.
Since everything changes permanently after taking just one round of antibiotics, it takes years of targeted nutrition and probiotic therapies to recover a balance in the body (do you even consider this?).
Next time, perhaps think twice before you get the prescription. See whether this is exactly what you need to become healthier?