Short circuited brain

So I have immense trouble making discisions, both large and small. It doesn't matter whether it is about what and where I am going to study next year or about which cookies I want to buy at the supermarket, my brain 'short circuits' (this is a dutch expression to say that your thoughts are going all around, nothing makes sense and everything is stuck). I just don't know what to do and in the end I almost always just walk away in order to avoid making a discision. However, I can't walk away from every choice I have to make, and I know I will just have to choose, but it is so hard. I don't really know what to do