Bacterial Infections & Vitamin D Deficency

I am getting fed up with one bacterial infection after another. In the past year I have had 5 doses of antibiotics for UTI, followed by a vaginal bacterial infection and then an infection under my arm. Now once again I am fighting another bacterial infection under my arm and antibiotics don't seem to be helping. In fact it is getting larger instead of clearing up.

If that wasn't enough bad news, I received a call from my doctor telling me to go straight to my pharmacy and pick up a prescription. Now I've never had this happen. It turns out she ran a vitamin D check while checking cholesterol. I am too low on vitamin D - way too low. I am suppose to be over 30 and I'm only 12. So now I have to push mega doses of vitamin D - 50,000 units twice a week plus 500 mg in calcium chewables twice a day too.
Apparently my body has not been fighting infection.

I have rheumatoid arthritis so I do not know if this is part of my immune system turning on me or not. I was told it would happen.
It seems I walk through one medical problem and about the time I feel I am making progress and relax - WHAM. I'm hit with something else. I am just finishing up selective nerve procedures in my back from a pinched nerve.

I turned 60 this year and I thought when I turned 43 my world turned upside down but it just keeps going downhill. I get up every morning just trying to keep going and do what I can.