When a question (of mine) gets upvoted, I get the points added to "reputation" but they don't show up next to the question as a +. Why is that? Sorry but your website does not have a comprehensive page explaining how the point system works. Thank you.
Please read each of the articles under Reputation & Moderation in the help section as well as review this FAQ post on the main SE meta. These posts detail everything that can happen to reputation numbers and why.
Some specific points you might have missed:
Voting on posts in the per-site metas (like the one your are on now) do not affect reputation. Reputation points are calculated from activity on the main sites only.
If 1 person upvotes a post and 1 other downvotes it, the number show next to the post will be 0, but you will earn the +5 (question) or +10 (answer) points and loose the -2 from the downvote. The reputation activity in your profile lists exactly what has happened that affects your rep.