Am I being too selfless?

My girlfriend of 6 weeks every now and then mentions how lucky she feels to be with me. She says she has wanted to feel special and be part of something special and now she finally has that after so long. But then she asks me am I just saying things she wants to hear almost as those she does not believe me. She also questioned one of my traits she says you are so nice and polite to people, but now wonders if it is a cost of my own happiness.

I've sat and thought about it for a while and now I'm starting to wonder if I am just doing that. It is making me question some of my actions. I don't think I am sacrificing anything, but I'm unsure.

I know now that she is a very special young lady and I am very lucky to have her. But when I am with a girl I truly give the best I can to her and the relationship. Other than some negativity and insecurity I always go into a relationship like this.

- I believe no one should make sacrifices in a relationship, because those things that make the person are part of the person.

- I give 100% every time to a relationship, but not a the expense of sacrificing something important in my life

- I give that person time and space when they need it, I don't want to burden them too much

- When I am with someone, I love for them to smile and be happy in themselves and for me to make them happy by my actions. In doing that I feel rewarded because a single smile means more than anything else

- I am very tolerant of people and mistakes they make. I know people are human and willing to give them a chance to rectify their mistakes and not have them feel uncomfortable because that's how I feel. I would not want to feel uncomfortable for making a mistake and unnecessarily punishing someone who is after all only human.

- I try not to use people, I am probably a bit of a drain on peoples emotions sometimes when I am a little negative, otherwise I will do all I can myself.

- If someone is feeling down, I would like to be there for them to hold them and tell them it will be ok and that I know they can do it.

- Occasionally I take a look at the relationship and in a positive light think of it as having a great chance of success. I know that is not always the case, but sometimes I think things 6 months down the line. 1 year down the line and imagine what it would be like.

- If there is something I really like, I tell that person (although all I get is rolled eyes)

When I am with this girl, I do feel sometimes that she will walk away from me, which I know will hurt, but I hope it doesn't happen, but I know I cannot stop that if that is what she wants. But I know I will take it hard internally because I felt like I would not have done the right thing.

Should I be feeling this way? I really don't know. I've been on my own so much I know enough already about myself and want to share my life with someone else. So what do you think?