Im having a very niched store, with the titles + descriptions of the product very informative and concrete. When I started the shopping campaign most search terms were relevant and I had sales. I only had to exclude a few searches each day (add negatives). But just few weeks in, there comes in a lot of very irrelevant search terms, and almost everything is irrelevant. Not 100% irrelevant but not even near the searches I had in the beginning. Because of this sales are down at none. I didnt change the titles or descriptions of the ads. The bidding strategy is manual CPC. Any idea why this is happening?