I need help!

Hello it's my first time here I'm desperate and I hope you can help me :(

I just ate about 3 cups of all bran cereal, 1 orange and a cup of yoghurt.. i ate too much! and for worst.. it was my dinner

I feel so guilty that I even thought of throw it up then i realize that it was insane... the worst part is that this is not the first time, lately i tend to over eat  

Try portioning out exactly what you want to eat in a meal, sit down at the dining table or place you normally eat, and eat only that meal. Do not eat anything else except what you've portioned out for at least 45 minutes.  If you're still hungry after that, you can consider your options. 

This is a good exercise in self control and the best way I broke myself of over-eating. 

Don't be so hard on yourself. I myself have these slip ups, tomorrow is a new day. So you ate 3 cups of all bran cereal not 3 bowls of ice cream.

You ate about 500 calories if you didn't have milk on the cereal (you didn't mention it).  That is hardly a binge and most of us would consider that a normal amount of calories for a meal. 

Of course, it's not nutritionally balanced and all that wheat bran might give you a tummy ache. 

To gain even one pound you would have to eat 3,500 calories over and above what you burn in a day.  Keep things in perspective.

Wow that's a lot of severe anxiety and panic over food that is healthy and hardly sounds frightening as a dinner (ok a bit unusual to chose bran cereal for dinner, but so what?).

So, not sounding like you over-eat at all based on this post.

It sounds more as if you may be trying to severely restrict your diet beyond safe levels and your body is merely rebelling and wants adequate nourishment and so you 'binge' (it's not really a binge because you likely need the calories).

Perhaps if you give us more stats we can help a bit more. What is your current height and weight and what are you trying to achieve? Do you have a history of compulsive thoughts and feelings over food?