Bigger female thighs in 2 months?

im going to be a sopre this coming school year but im so skinny everyone thinks im 11 years old. i want to be a little thicker by the time school starts, in about 2 months, but idk how. my thigh measurement is about 16 inches, but i want to be anywhere between 18 to 21 by the time school starts. anyone know how?!?!!?!??! pleaasee helppp. same with my arms. my upper arms are 9 inches so i want them to be between 11 and 14 inches. helpful answers onlyyy. im really insecure so this would help alot. ive NEVER been able to gain ANY weight no matter what! im a vegetarian so i already know that has alot to do with it.:( please helppppp. plz n thank uu!