How to deal with immature feelings?

I'm a self aware person, with a good mindset, and tend to have a decent amount of control over my behaviors.

But my feelings are very immature.

I feel sad and frustrated over small matters, like hearing someone yelling, a child clinging to me, noticing that I'm alone despite it being freeing, and even during good days, it always makes me feel guilty about them.

When I offer help, or give someone a gift and they get refused.

When someone blocks me.

When my family spend time with others other than me, this feeling of not being chosen as their favorite person hurts me on a daily basis.

The idea of my siblings choosing to spend time with their friends other than me.

Seeing them improving and enjoying their time.

Instead of feeling happy for them, I feel hurt.

I can clearly think in a positive way about them, I know they have their reasons, they're not evil, and I can control my behaviors and words to not make them feel guilty about not choosing me, but my feelings are a different story.

My feelings... they rise up negatively for wrong reasons.

I always feel jealous.

Even while knowing that comparison is the thief of joy, and knowing that everyone has their own ups and downs.

My feelings just... don't catch up at all.

I hear that thoughts lead to feelings.

But it doesn't work that way with me at all, even while having a correct positive mindset, my feelings are always on edge, experiencing so many negative emotions every day.

I can't ever feel peace.

Through thoughts and logic, I'm grateful, as my life, even while living alone, is a decent life that is privileged.

But I can't ever feel the emotion of gratitude.

This sense of.. peace, that tells you that you don't need to have or buy anything more.

I can't ever feel it.

It's the reason why I fail all my relationships.

Family, relatives, friends, and even previous romantic relationships.

I can never emotionally accept people's flaws, even when I understand them.

I can't ever feel "enough" with what I'm given.

Even when I'm given their time, my feelings always want more.

Always wanting more and more.

It never stops.

And I don't know what to do.

It's the core of all my problems.

I over eat, I keep trying to numb my feelings down with music, video games, and walking outside.

But it all feels like a pathetic attempt to cope.

Always feels like I'm faking them.

This feeling of attention seeking never goes away, it's so bad that even when nobody knows about me, I think about other people when I choose to do a taste based activity (Like listening to a certain song because it would me look like a person with a cool taste, not listening to it for my own want).

I can't feel the happy times.

The bad times are amplified.

The quiet alone times are too loud.

Peace and contentment are impossible to achieve.

What can I even do at this point?

I'm 19, almost reaching 20, but the intensity of my immature feelings are similar to my 7 year old brother, just directed at a different direction.

I'm failing subjects in my college.

Studying is a drag for me, I can never sit down and focus without my feelings getting overwhelmed.

The concept of discipline is like a myth to me.

What can one do when their feelings are this much of a mess that's ruining their lives whole?