It's an interesting question that has a lot of facets to it. Generally speaking, you should try to make the most objectively correct decision, and if the results don't work out you just have to be okay with that because in the long run you'll come out ahead. Focusing too much on the results is an easy trap to fall into, and one you want to avoid at all costs. In Vintage especially, these decision points extend out well beyond the tournament itself because deck choice and sideboard selection are so important.
In your case, perhaps the decks that you have been playing have not been particularly well-suited to the metagame at the events you have played in? Or perhaps because you have been switching up decks you have not been playing optimally or have not had the time to really fine tune a list for your metagame? Perhaps you are putting too much pressure on yourself to put up the results that you think you should?
I do not think that Vintage is a top deck battle at the moment, it seems more balanced now than any other time in recent memory. Just my thoughts, no criticisms intended. Hopefully that helps at least a little!