Amazon sales algorithm?

Is there an algorithm on Amazon that prompts more sales one day compared to another? This is my 3rd month as an Amazon seller and I have some days where I have over $500 in sales and others, like the last 2 days, I only have $12 in sales. We were going strong selling a 15-20 orders of a product for about a week then the sales stopped coming in. I feel like there’s some sort of algorithm that promotes sales one day and changes the next. Does anyone have any insight to help me understand?

Background: I’m doing RA, selling via fba and fbm. I check inventory pricing daily and generally have the lowest prices. I’m not doing any promoting/marketing.