What are some signs of vocal damage?

i am a singer. been singing since as long as i remember. I used to be able to burst through a brick wall with my voice and the same tone at the botton lifted to the top register. but recently i have been having some problems. in my lower range it still is good, and i still have a very big voice but not like it used to be. one day i can sing a song blow it away hit ever note strongly. then the next day i can sing the same song the same way and at places my voice will thin out or it will sound like a tear is in my voice. i ll have to struggle to hit the same notes that i just sang the day before! even my talking voice is crazy. one teacher told me to talk an octave higher than i usually talk because when i talk low it hurts my vocals and it feels like it is pushing down on something when i talk. what should i do ? i love to sing and i cannot imagine my life without singing. HELP