the whoas of being a girl

Just venting... but ugh! Take pills to kill a UTI only to have them cause a yeast infection! I swear my downstairs is broken! I do everything I can to prevent both and it still happens. Am I missing something? Anyone have suggestions? I drink lots of water, wipe front to back, threw away all my husbands and my lubricants, bought cotton panties only and still!  Grrrrr.