A sudden drop in sales is scary but it has been only a very short time since you changed the price. The sales drop could be for any reason and is perhaps unrelated to price.
I’ve gone back to reread some of your original messages. I noticed a couple things on your metrics tracker and your other comments:
After your 1 Euro price rise (which is not a lot), you are currently priced 1 to 2 Euros LESS than your top 2 competitors.
If the buyers are truly frightened away by that 1 Euro price rise then you need to ask yourself if there is something wrong with your product because buyers don’t want it even though it is still LESS than your competitors. I don’t say this to scare you and I don’t believe it. I’m just trying to illustrate that things are just as simple as sales dropped because I increased my price for 1 or 2 days.
I think you need to grit your teeth and test for a longer period to get better data. (and personally I think you should test having the same price as your competitor).
Of course, it’s all up to you. If you are uncomfortable with how things are going, you can reset your price if you want.