G'day Beccah, quite obviously you are new to this kind of problem, and
quite obviously you have substantial sensitivity which is currently
controlling your life.
I would suggest you begin the exercise at your home, this needs to be
classed as your territory.
Anything in the home or anyone entering the home need to obey specific
laws, there is no relaxing this aspect.
This begins with anything aromatic, any chemical, any animal, any dusty
product or anything you deem that may cause you a problem.
This is absolutely important, and provides a place of safety for you.
(after it is carefully examined)
Never let anyone in your home past the front door unless they test
acceptable as far as scent or aromatics go. Rigourously enforce this
rule, people soon learn and accept your circumstance, relax it and you
will pay dearly.
It would be adviseable to undertake a desensitisation method of some
description to try to reduce your dependence on any drug support.
You need to become significantly more observant, especially when ever
you go out anywhere, or are present near disgustingly fuming persons
wearing ridiculous colognes etc. It is a good idea to make it known
that their substances are likely to kill someone with an asthmatic
problem, most of these kinds of people are absolute morons. (standard
answer being "duh"!)
If you enter a restaurant or whatever always observe where the aircon
outlets are and sit nearest as to not have problems from others. The
same applies on transport and any location in any building, this takes
a while to learn. Even walking down a busy street, walk on the upwind
side this reduces vehicle pollution effect.
When you refuell your vehicle observe the wind direction and select a
bowser best suited to allow you clear air.
Do not tolerate substance exposure unless it is absolutely neccessary,
it is a mistake to suffer any exposure whatsoever because it is
substantially difficult to reverse the effect, a few minutes exposure
may take days to overcome it's effect.
You need to understand the buteyko breathing principle, essentially the
ability to maximise any air breathed and develop an ability to breathe
sparingly in contaminated conditions.
This particular ability is substantially helpful especially in
supermarkets and places like that.
It does not include any deep breathing and any breathing should always
be through the nose.

With regard to exposure in relatives homes and that kind of thing,
excuse yourself and avoid it.
Cat dander effects (especially) can take years to abate in homes.
Anyone having sensitivity problems and suffering asthma that is able to
overcome the asthmatic element normally never fully overcome the major
problem sensitivities, the degree of everlasting effect is obviously
dependent on the period they have had their problem.
With regard to attending theatres and public places where close public
mingling and rebreathing others air is unavoidable, expect to suffer
with any contained respiratory illness, the worst description of this
is long-distance el-cheapo airlines.

In keeping with your problem description you would understand that you
catch anything that is going around to a worse degree than others, you
would also likely have an antibiotic useage rate beyond any normal
expectation.

It would be in your interest to consider regular probiotic use, and
also google "Gary Huffnagle" to learn and understand some of the reason
for your problem.

Cheers, Merlin.