My friend seems to be more interested in our other friends than me? :(?

well, one of my best friends named lindsey, has always been by me..through everything. But ever since she met another one of my friends. (taylor) all she cares about is following him around all the time!! I try to talk to her & she ignores me. I even told her how I was feeling, but she kinda didn't care. I don't know what to do! Sometimes she's the old lindsey, & sometimes she's not. Is it time for new friends?