I want to say that "everyone has that one friend who you love to death, but doesn't give as much to the friendship as you do," but hopefully that's not the case. Hopefully, all of your friendships are strong, supportive, and help you become a better you. For some of us, that simply is not the case. My best friend throughout middle school, high school, and my first year of college was the coolest person ever, but it came to the point where I was the only one putting effort into the friendship.
You know what I mean... I was always there when she needed, let her stay at my place for extended amounts of time when needed, etc. But when I needed something? She was nowhere to be found. We would make plans to meet somewhere for dinner, and I would show up and wait... finally I would call and she'd say she had other plans or will be an hour late. What? You make plans in order to follow through with them because standing someone up like that is simply disrespectful. In the end, I felt super guilty when I finally ended the friendship, but you know what? Friendships aren't supposed to be one sided. Friendships aren't supposed to make you feel lonely and like you're not important enough for someone. Friendships should be character building and make you feel like you have a buddy to go through life with.
I'm here to tell you that it's okay to find new friends. Even if you and said person have been friends for 10+ years! People grow, change, and find new niches. There's nothing wrong with growing and finding new people who fit your new lifestyle.
My hope for you all is that you learn that these bad friendships are not worth it and that you find ones that are. Do yourself some good and just let that friend go.