Hi! I'm 23 Years Old And Weight Around 55kg. Ive

Hi! I'm 23 years old and weight around 55kg. Ive been gymming for atleasat 6 months. In the initial months i saw some improvement. But it has stopped now. I work out 3 days a week
day 1 : Chest and Triceps
Day 2: Back and Biceps
Day 3: Shoulders and legs

i eat 2eggs with toast and juice for breakfast
4 roties with sabji and curd for lunch and the same for dinner
i eat 2 bananas before gym and a homemade shake after work out which consists of peanut butter, milk, oats and yogurt.

I need to put on weight as i am 6 and look very thin. I am a vegetarian.
Please help me with some fruitful advice.
Thanks
Ujjwal Prabhakar.