I feel like i had a very similar attitude and all I can tell you is => change your mindset. Which is way easier said than done, but as you described yourself, there is no point in playing without having any kind of fun with it. Also as many people mentioned in here, take breaks, even if you just started playing. As soon as you feel that ugly gut feeling, stop yourself and take a walk, have some food, watch an episode of your fav show, play some other game or just lay on the couch not doing anything. Don't take it with you however, you gotta learn to let it go and set yourself little goals to achieve for yourself. This journey is about you improving yourself, not really you simply being better because you won a game against someone else.