I made a smoothie with oats, peanut butter, banana, honey & milk for weight gain and it was AWFUL! What am I doing wrong ?

Hello,

I made up a smoothie (for weight gain) by blending milk, oats, banana, honey and peanut butter. When i tasted it, it was soo bad, I almost vomited!

There was a very strong bad taste and smell of oats. A quick search on internet reveals that best oats are rolled ones which mine aren't. I used these oats bought from amazon that i usually make an oatmeal from :

Although advertised as such, they werent rolled oats, it looked like the rolled oats were partially grinded to make these oats.

Can someone point out what mistake I am making or is it the oats. I seriously hope that I did something wrong and there's still hope for me to gain weight using a tasty smoothie.

Thanks alot