Nextoptim, Cpafireboost, and s3amazon Pop-Up ads

[pasi458]

Recently I was hit with some scammy ads on Firefox. I wasn't on any sketchy website nor did i download anything, it just happen out of the blue. Thinking I had a virus, I did a quick-scan with Norton and nothing popped up. I'm wondering if this is normal or should I be worried?

 

[pasi458]

Also this happened right after I was on the Mobafire website