Hi Katejo
I used to get lots of UTIs.
At one point (after a urine test it has to be said) Nitrofurantoin was given. It didn't really work for me, took a couple of weeks to get any relief only to get the infection back after a couple of months. The only thing which worked for me was Co-Amoxiclav. Tried it first in 1997 then didn't have UTIs till meno hit in 2012/13, did the Nitrofurantoin dance again. Still didn't work, after much begging I managed to get some Co-Amoxiclav again. Thankfully, haven't needed it since.
Mind you, what works for one person doesn't for another.
Good luck with the Cefalexin and enjoy Berlin.