Replacing an entire wardrobe... finding it nearly impossible as much as it is necessary

Life threw me for a loop due to some health issues, and because of that I found myself without employment. It has been a 10 year journey, with some sporadic job opportunities that did not pan out.

I am back in the hunt for employment (again) but am realizing that all of my attire no longer fits as it should due to weight loss. I have merely hesitated in trying to purchase "workplace" attire because I did not know how much more weight I would lose; and what I do have is so loose fitting that I look unprofessional.

When I interview, I often hide this by layering a zipper sweater over a shirt and tie; and the sweater is long enough to hide my cinched/bunched up pant waist. My struggle is that if I happen to get a job, I am going to have to have enough articles of clothing which I can mix and match to look professional.

Second hand stores are an option, but I am realizing that with what financial resources I do have, I am finding it nearly impossible to replace an entire wardrobe. Advice/remarks appreciated.