a UTI and a yeast infection... typical changes?

Ultimately I'm fairly certain I will be referred back to the obvious...I should consult my yno...However out of curiosity, I am 28yrs old up until 1mnth ago i have never experienced a UTI or a yeast infection...Now i have had the pleasure of both. Also, after having my normal menstrual cycle, my breasts remained sore and swollen and seem to have grown slightly. I also got a yeast infection and within one day of the infection my period returned almost 2wks before it should. I have taken 2 pregnancy tests both were negative...Is this part of the typical changes your body goes through? None of my habits have changed, no major stress in my life and literally everything from my diet to excercise to intimacy habits have remained consistent. Is there anything that comes to mind other than the obvious recommendation I stated at the beginning?