HomerSimpson: I chose 'Stay Alone' for Sundays
That is indeed the reason for your problem. While set to 'Stay Alone', you do not gain any Interaction Points and thus any amount of Relation Points percent is still resulting in zero.
That's exactly why I'm trying to avoid it, though I'm not sure if I'm going to manage.
HomerSimpson: look for other ways to keep confidence up.
The 'easiest' way to keep a high
Confidence value is to perform well during a match and to predict that. The better you manage to predict a positive result (6-10), the higher your confidence boost. Unfortunately, I am sooooo average that I always perform a solid 5 and thus never get a boost (hints and tips welcome! ;))
The other (preferred over 'Stay Alone') way to influence your Confidence is through interaction (Interviews/direct interaction). I'm hoping to get another round of 'Wish him luck' boosts from my marvellous team before the first match in the new season *puppy eyes*. The problem here is (according to the Help forum), that your 'Friendship' value determines the effect.