Not sure if it has been mentioned before, but all Paradox titles are titles where failure is built into the game, and can be fun in it's own right if you adopt the right mindset.
In this case, you were too aggressive, and you were penalized as a result. You should learn from this, and try again, with more mechanics in mind. You will feel 'defeated' another number of times (Even wars which don't actually end up in you technically losing the game but still end you up losing land can cause that) and the only right mindset is to see what went wrong, and try again.
it's quite possible that you can't keep it up. That's no problem either, but I'd advise you also not to play EVE or the X series then
In this case, you were too aggressive, and you were penalized as a result. You should learn from this, and try again, with more mechanics in mind. You will feel 'defeated' another number of times (Even wars which don't actually end up in you technically losing the game but still end you up losing land can cause that) and the only right mindset is to see what went wrong, and try again.
it's quite possible that you can't keep it up. That's no problem either, but I'd advise you also not to play EVE or the X series then