As others have said, the issue here isn't whether your feeling is "correct" or not. The feeling is there, you can't logic it away. What you can do is decide how to deal with both the situation and the feeling about the situation in a constructive manner.
You've said that you are a very competitive person and that's what drives you. That's not wrong in and of itself. But there are a few things you need to consider here:
Competitions usually means that someone wins, and someone else loses. If you are seeing this as a competition, that means you have to learn to accept the possibility that you will not always be the winner. You need to be able to deal gracefully with that.
Not all competitions are short races. Some are marathons. The person who is consistently ahead of you early in the race may not be there at the end. And some competitions consists of several smaller races - even if someone wins the first five, they may lose the all-over competition to someone who was behind in the first races but pulled ahead in the later ones.
Not all competitions are individual ones. Some are for teams to work together against other teams.
You now have a huge opportunity to use these facts in order to get better both at your job and at being a competitor.
I'll start with the third point, that of seeing this competition as one for the team instead of for the individual. I'd suggest that you start focusing on the team rather than just yourself. This new person, is he helping the entire team to get better? If so, your team has scored an advantage by getting him on board. Use it to your personal advantage too - learn from him the things he knows that you don't, offer to help with the things you know that he doesn't. If he's getting all the questions from your coworkers, he may be feeling stressed out or put-upon and wish for some time to be able to work in peace. You can offer to show and help others when he's busy - but remember to do it with a genuine offer of help, not as a ploy to get the credit.
If you can see him as your mentor/coach/team leader, rather than your direct competitor, you will move to a head space where his skills are your assets as well as his. They're something you aspire to rather than envy, if you see what I mean.
For the first and second points - when you feel that you've lost, don't stress over the loss. Instead, analyze what happened. What was it he did better than you? How did he do it? Could you do that? Could you think of some way to do something even better the next time a situation like this arises?
You should also be aware that there is a fourth factor here:
- The competition may not be about what you think it's about.
If you want to be the person that your coworkers turn to with questions, you should know that it's not only the knowledge in your head that matters. It's also the way that you behave towards them.
If I have a coworker who's very much into competition, who gets unhappy if they aren't considered as number one, I personally will be less likely to turn to that person for help. It makes me feel as if they're not interested in working together with me, that they are seeing me as a prop for their own internal ranking system rather than as a coworker that they should cooperate with in order to get the job done as efficiently as possible.
So, to be the go-to person, the one considered both knowledgeable and approachable, you need to not only know a lot, you need to also be helpful and kind in sharing your skills and knowledge. You need to help others, and be completely OK with the thought that this means some of them may surpass you later. In other words, don't let your competitiveness stand in the way of winning.