Hi Daiseykins
It's impossible to be upbeat all the time and you sound like you have reason to feel less than boyant at the moment. It must seem like one thing after another. It could well be, as you say, that your immune system is low and so you are picking these infections up. It is good that there is nothing more than infections.
I hope that you start feeling a bit more yourself soon but do allow yourself to be 'down', we are allowed! And moan here anytime you like.
Take care.
Mary