Something wrong every week

So since 17 weeks of pregnancy I've had something wrong, first a kidney infection which I was hospitalised first, then they thought I was going into labour! I'm being watched for pre eclampsia as severe headaches and protein in my urine! Next a water infection, so loads of antibiotics which has caused thrush, which is very painful, I now have a chest infection and had my urine dipped Friday and they found blood in my urine! Not sure why I'm so run down all of a sudden and why these things keep happening? Am I just unlucky or is my body not coping with all the changes in hormones? I'm 21 weeks pregnant today. ?