There is the "simple cystitis" and the "haemorrhagic cystitis" which looks much more dangerous, since the urine can be really blood red, even with sort of clots in it. This is due to the infection affecting the mucous tissue of your bladder. I guess that is what is happening to you just now.
It is not really very much worse than the simple cystitis,but the fact that you are not better even though you did all the things like drink more (at least 3 litres/day) etc. shows that the bacteria are liking it in your bladder. In order to prevent things from getting worse, i.e. the infection "climbing" up to your kidneys, you should see a doctor asap and have an antibiotic such as cotrimoxazol or ofloxacin.
Having pains in your lower back that persist, could mean your kidneys are affected too. Then the doctor is even more important.