you might indeed have a bad compass, or rather a compass that does not work well with your particular style.
What is the brand and model? I can offer you a Moscow 9 or a Silva Jet to lend and try out when you come up to Uppsala. I also have another very nice Silva (don't recall the model)that I find pretty useless because the hole for the thumb isn't cut out, so I can't touch the map... turns out that is a deal breaker for me. It was a gift, so I would be happy to gift it on to a happy and deserving home.
I have a Silva Jet. But it just seems too shaky when I run fast. Since it is such a pivotal part of orienteering I want to give it more thought. Trying out yours when I'm there would be eggs-cellent.
Excuse me. Upon further examination, I have realized that I actually have a Silva Nor6, which is not nearly as high end as the Jet--shows how much thought I've given to it. Oops!
I have a couple of models, some with a narrow needle and some with a broad needle. I prefer the broad stable ones, as a rule. But I am not an expert with the compass either, and I am trying to work on my technical skills especially in areas of thicker vegetation and low visibility.
I guess picking a compass falls under the category of "control the things that you can control" and maybe also "choose something you like, and then don't mess with it any more"