health issues after quitting smoking

Hi:  I have been told by several people that they felt worse after they quit smoking, than when they were smoking.  The issue seemed to be breathing problems upon exersion, or just plain climbing a few stairs in the home.  The other is that they catch every virus going, so my question is, will taking cod liver oil, as well as zinc, vitamins a, b, c, and e, help to build up the immune system and avoid alot of these viruses and hand washing often as well?

What can I do to keep my lungs healthy through the healing process, is there a way to avoid all the breathing problems associated with this?  I do have airborne pollen allergies as well as ragweed problems, but they mostly deal with my ears aching or blocking and the odd sinus headache, and sometimes a sore throat.  That I can deal with, im more concerned about the breathing with the lungs and the viruses.

I am feeling anxiety over this, since one woman mentioned she had to quit her job because of breathing issues which kind of frightened me enough to not quit now. I certainly cant afford to quit my job, because i want to quit smoking. 

I thought I should also mention that I am going to be using the nicotine patch, and upon my first try of them, I had no problems using them.  They did curb the withdrawals and I felt okay.  The only reason I stopped and started smoking again was because i heard about these awful side effects on our health after quitting in that first year.

Hopefully you can put my mind at ease so that I can get right back on the patch with more confidence.

Thank you for listening to my concerns...