Body hurts

I am so skinny man, I can't even imagine doing the deed with my body type cuz I get the ick
I sit down too fast and my knees will start aching. I tried all kinds of diets but nothing grows. I eat meat, So much meat but then why. I lost few pounds again, the thought of it makes me sick to my stomach. I am not severely underweight, just a little as of now but if this continues, I fear by the time I get a partner or go out into the world and start doing some physical labour, I'll be only sticks and bones. I exercise but my body aches so much. I thought it will get better but... no result T^T Cutting down on junk is hard but I eat heavy meals side by side; eggs, fish, rice, chicken, fruits, etc. What am I supposed to do?