Life sucks... i am a sophmore in high school and need help bec i am very depressed...;(?

i am a 15 1/2 year old boy who is very high pitched and have a small . i attend auburn high school in alabama. whenever we lift weights or do any exercises with 8-12 graders i end up being the slowest and doing the least weights... in running all 8th graders finish before me and am soon to become a junior. i need help please i am 5'5 and always made fun of bec of my voice and girls never take me seriously they just look at me like a kid. its embarrising that 8th and 9th grade kids can do better and more than me. please help me. when am i going to hit my growth spurt? what about puberty? i need help please bec i cant take depression anymore? when is my voice going to get deep? please help me with serious responses please!