Are bacterial infections and fungus infections the same as a yeast infection?

i got a yeast infection ( i think was from my bf at the time ewww ) it wouldn't go away then when it did, it came back again. but this time the doctor said it was a bacterial infection so she gave me meds it went away then it came back again but the doctor said it was a fungus infection this time (i went to the same doctor every time) are they all the same thing... wut makes u to get it... is it transmitted ually?... plz just answer my question dont give me a hole buch of bill ****