sometimes you not know your worth and maybe you feel low. I recommend you never dishearted if you are sincere with your work, motivation comes from different sources.
you should try to do something new...like you can learn a language or you can make an open-source project that helps others.
The biggest source of motivation is when you helped others in work.
Never compare yourself with others. just try to do something better and better....then you will stay motivated.
Success is nothing more than a few simple disciplines, practiced every day. (Jim Rohn)
you need to ignore naysayers, demotivational peoples, or everything that demotivates you.
keep patience and grow slowly...because a tree grows in years become like a tree.