I would advice you to not neglect any feeling of diziness or anything anormal that you may put aside to win the match ! In the long run it is your good health that will allow you to continue playing (and winning if that's your wish) matches. Also, to try to sleep well in general but especifically before a competition, in order to avoid any injuries due to exhaustion or inadvertence - and so you can do your best !
How do you feel before a match or a competition ? Do you feel the benefits from doing sports even if you don't reach your goal or if you loose a match ? Do you feel safe around your team mates ? Would they help or support you if you shared your difficulties ?