Most Helpful Guy
It's definitely normal to feel different around the one year mark, but that doesn't mean this is what you're going through right now. Talk about it with friends who've had longer relationships.
Most Helpful Girl
You won't feel the same "fuzzy" feelings you felt in the beginning when the relationship was new. As a relationship goes on, things change, that's just the reality of it. Typically, feelings intensify and become deeper so while you may not feel the exact same feelings you had in the beginning, that doesn't mean the relationship has run it's course. Generally speaking, the relationship should end if you realize you are no longer happy with that person. If that person doesn't make you feel good or if you feel like the relationship is causing more stress and heartache than happiness, then it's probably time to end things.
For your situation, I would say there's nothing wrong with how you feel. If this is your first long-term relationship then it's understandable that you aren't sure why you're feeling different. It's completely normal for things to start bugging you. The longer you're with someone, the more you start to see their flaws and maybe pick up on their habits that annoy you. That doesn't mean the relationship has run it's course though. You should probably just spend some time thinking about how you feel and then decide if you want to stay in this relationship.