My ads seem to take off out of the starting gate, then fizzle by day 3 or 4. My current campaign is for a one week 0.99 sale for the newest book in the standalone series. Day 1: CPC 0.09 and CTR 10.51%. Day 2: CPC 0.10 and CTR 8%. Day 3 (it's still morning) CPC 0.14 and CTR 5%. Conversion was high with sales for all three books in the series and an uptick in KU reads the first two days. It's slower today but there are a lot fewer clicks.
This seems to be a pattern for all my ads, so I keep turning them off and trying new ones. At first I thought the drop was because I increased the budget ($5 to $5.50) so I just started at $10 for the current one.
Do I just need to keep changing them out every few days? Is this normal?