Hello dear
The above mentioned symptoms are indicative of depressive symptoms.This could be due to your life situations and comparing those with your sister's. It is very important to understand that every individual is different, have different abilities and different opportunities. You might be good in something and your sister might be good in something else. Try to write down your strengths and count your blessings. If required proffesional help kindly consult a clinical psychologist either online consultation or meeting in person.
Health Tips
write down your strengths, think positive, meditate