Have you called your Oncologist? He will suggest what to do to build up your immune system. I don't know how your body works, but I'm a breast cancer survivor only 1 & 1/2 years, my body seems to catch every illness going around my immune system seems to fail catching and killing germs. I do belong to a Bosom Buddy group and what was told to some who have had low blood count was to call their doctor immediately. Tell the doctor how you feel and if he is not there contact either your primary doctor or an ER clinic and ask what they would suggest. From what I've experienced myself we are so used to getting colds flu's and dealing with the ailments ourselves that we have the same mentality when we have cancer. The difference is that our bodies are not functioning appropriately, so we need our doctor to know even little things like colds, constipation, etc.
Let me know what he suggest or treats you with. Hope your feeling better soon.
Agape' a fellow cancer survivor Carol K