I've been pretending to place football bets for my friends for the past 4 years when in reality I pocket the money for myself
Why would you deceive them like that?
I can't be honest with them about it because I will feel that they think less of me.
They are going to think less of you when they find out the real truth. It was wrong to betray the friends that trust you.
It's fine I had a rough 4 years and then I should have a good 4th year now since I took their money.
It's wrong to betray your friends the way that you did. Essentially, it would appear that you stole their money. You should avoid doing something like this in the future because you will regret destroying your friendships.