Is it normal to get tired of your friends?

So my bestfriend and I used to hang out every day, every night. We had a lot of fun, but after spending every day together for approximately 6 months, I could not take it anymore. I love her and I loved spending all that time with her, but it was too much for me. I sent her a text telling her that I needed som space to sort out my problems and that my problems had nothing to do with her. She seemed ok with this for a while, but now, whenever I try to contact her, I feel like she rejects me. Maybe that is what I deserve but I had to say something, she tired me out.