Hi Kristy,
Everyone has different levels of how much they can do/can't do. It sounds to me that you have alot on your plate, though. If you will consider "health" supplements, here are some things that have helped me alot, especially when antibiotics just don't help. You can find them at most health/vitamin stores. Whole Foods Market is my favorite, and they will help you find the best product for you. I would suggest getting a book or two about "natural cures" and supplements so you don't feel too over-whelmed. There are tons of truly beneficial and natural as well as tons of garbage products out there, it can be confusing to walk in looking for supplements if you aren't sure what to look for. If you can get to a really good health food store, the people there are always very knowledgeable about products.
1. Pro-biotic capsules. These replace the good bacterium in your intestines that get wiped out from both day-to-day life but especially from taking anti-biotics (as antibiotics wipe out the good as well as the bad bacterium). Do you tend to get yeast infections from taking antibiotics? Pro-biotics will both prevent those, and clean up existing infecs. (I used to get those alot, not anymore.) My personal favorite is "Jarro-dophilus EPS". My kids and I take one capsule every morning, and we avoid all of the intestinal/diarreah stuff that other kids get, and I haven't had a yeast infec. in years since taking it. If they do get diarreah, taking 2 capsules a day clears it up within 24 hours. Pro-biotics are safe for babies and toddlers, too. There are liquid brands for the little ones.
2. Astragalus root capsules. Have been buying the brand "Nature's Way" lately, as it's standardized/proven to actually contain the beneficial element. It's an immune system "helper" that the Chinese have used safely for centuries. Alot of people might suggest echinacea, but I have read lots of studies in natural health magazines that find it has been proven ineffective.
3. Vitamin C: but make sure it's buffered and time-release. My favorite is the Solaray brand that is "two-stage, timed-release", 1000 mg. It may give you diarreah the first few days: if so, keep up the daily EPS, and if you still are having trouble, switch to 500 mg. daily.
Having tended bar (as a non-smoker) for 7 years during my 20's, I know that second-hand smoke definately doesn't help the immune system. You may have especially sensitive sinuses/lungs, too. The above three things might hopefully help you alot while you are working at the club. And probably you already do, but drink tons of water while you're in the club to flush out what you're breathing in.
Hope you feel better/great soon,
C. N.