Is it normal to feel lonely if you have friends but they are too busy in relationships to make time for you?

I think the romantic feelings can easily divide and separate people from each other. Think about what happened to Todd and Copper in the Fox & The Hound. Copper became brutal and aggressive under the training of his master hunter Amos Slade and his mentor dog Chief. Likewise Todd grew to develop a deep attachment to Vixie and they decided they would mate and be a family together. I know at the end Todd and Copper somewhat settled their differences but sometimes I think hatred, jealousy, romance, and neglect all have tragic ways of tearing close people apart emotionally so they don't want to spend time together anymore.