My white blood count was extremely low after my first chemo so I had to give myself nuelasta injections (I think that's what it was called) about 24 hours after each of my subsequent chemo treatments. Not sure if it's the same as what you will be having. I think the purpose of them is to boost the immune system - which chemo knocks out - to minimise the risk of getting infections.
Don't know if they made me feel any less unwell than I would have without them but I never did get any nasty infections or need to be hospitalised or anything like that. So I guessed they worked.
Sorry to hear you're about to undergo chemo. It isn't much fun. There are so many possible side effects which you may or may not experience - everyone seems to respond a bit differently. But I think most of us find it's not quite as bad as we fear. You have to be prepared to take it easy on yourself, accept the help and support of your friends and relatives. You do get through it though. My chemo finished last August (2012) and I'm feeling great now. In fact on Sunday I am going to do a 5km fun run. Just want to let you know that despite the rocky road immediately ahead of you life can get back to normal. Janet.