Tips on eating small meals

I believe a main problem of mine is I am eating too much, too often.

I'm a slim guy 5'9 130 lbs but when I eat I pig out and then wonder why my stomach feels bloated and it's hard to breathe.

I think I'm putting too much food into my stomach throughout the day and it's just too much for my stomach.

So for example if I wanted a sandwich and chips, I should just eat half of the sandwich?

It's hard for me to imagine just eating less but I feel I need to