Thank you for sharing your emotions so frankly.
You are reading too much in bad moves, losses and wins: they are not judgments about your whole self; you are not a loser when you lose or a master when you win.
We all play bad moves, be it because we are tired, as @Conrad_Melville mentioned, or because most of us are not go masters. That’s life.
Every single loss and win is just part of some average that defines your level (the best two players in the world, if they have equal strength, should lose 50 % of the time!). You have the level that you have: are you stronger than a beginner? you bet. Are you weaker than a professional? you bet. Most of us are somewhere in-between and there is no shame in this or it would be unnecessarily difficult emotionally to climb to higher ranks.
You can embrace your mistakes as golden opportunities to learn something. Same thing for your losses. Even more difficult: learn something from your winning games, for even in a won game there might be mistakes, things that are perfectible, or inspiring moves played by our opponent.
I’ll be frank and blunt: if you sometimes suffer from a mistake or a loss, or become arrogant because of a win, you are taking yourself too seriously. What is your goal? To prove to yourself that you are incredibly gifted at go and should always be the dominating player, or instead to improve yourself because getting stronger is a challenge that you enjoy taking? I would suggest that on the path to your peace of mind lies humility and having as a goal the improvement of your imperfect play. Thus you will be more open to the great joy of learning and feeling progress—including through your current weaknesses.
My 2 cents. 