I Am 18 Year Old My Voice Became Too Harsher.

i am 18 year old my voice became too harsher. sometime the pitch of my voice become so low that a person so close to me can't able to hear my voice . sometimes when i talk only air is came out, no voice is there. i can't speek loudly,which hesitate me. due to this i have very low confidence. please suggest me the tip to stop this.