How do I keep it all inside, but not blow up on people?

You shouldn't keep it all inside. If you feel something, you need to allow yourself to feel whatever it is that you feel. It's always healthier to talk out, or write down what you're feeling rather than keeping whatever it is that is troubling you or making you feel bad locked inside. You can take a walk, write down what you feel, focus on your breathing, practice what you would say, think about how you're feeling and how to deconstruct your thoughts. These can calm you down and allow your to control your possible feelings of frustration or anger.

There's nothing your can do without unhealthily suppressing your emotions. You can find a person who you express yourself to, either it be a listener or a close friend.

I found that writing my thoughts and feelings down into a journal helped me to not blow up on people, as it was a kind of release/outlet, yet still keep it to myself, as the journal was/is for my eyes only.

The idea is not to bury it but to deal with it. With the correct time and space you can deal with whatever it is that you have inside so that you don't blow up because you have too much suppressed inside.

You can't. You have to talk to someone. It will make a difference because if you do 'blow up' then it will have consequences. Don't worry though you can talk to someone about things here, it will truly help!

The worst thing you can do is keep it up all inside but you can come onto sites like this and just talk it out. Even start to write a diary if you don't already have one. When you're upset, write your feelings on a memo in your phone, on a piece of paper or talk to someone anonymously.

When I am struggling to control strong emotions I will take a "time out" to write down my feelings. I keep a small notepad with me at all times. I will take a few moments and write out on paper exactly what I am feeling and then why I think I am feeling that way. Usually just having the chance to focus on writing instead of reacting helps to control the emotion. Later, when I have more time, I can re-read what I've written and reflect.

I recommend counseling. One things for sure and that is keeping things inside is unhealthy it is one of the main reasons people blow up at each other. Find a way to express your feelings look for passion.

It is difficult to keep things bottled up inside and it effects not only us but also others around us so maybe one can keep a journal or diary where they can write it down , it sometimes makes people feel better.

Blow up not on people. You don't deserve to keep it all inside, that's unfair and unhealthy. You have to let it out in a good way, not on other people. This can be through screaming into a pillow, breaking something you don't need anymore, listening to loud music, scribbling aggressively, etc. Whatever it is, it gets out all your emotions. And it makes you feel calmer. Therefore you can live with not blowing up on people, but not bottling it up inside which will just make the urge to get it out on other people even stronger. :)