So Called Friend

i have a neighbour who also became my friend. When I was not studying I used to get time to join for potlucks with that friend and a group of which she is part of. But later I had baby and after he was 1 yr I started studying. I then hardly used to get time to meet them for events. They then stopped calling me and they created another WhatsApp group which was ok for me. I agree that since I don't join them they stopped calling me. But whenever I used to meet these friends I used to talk and be nice to them. This lady was also good friend of mine. But once they removed me from the group, she kind of showed disinterest. I used to take initiative to talk whenever I will meet her. But later I also got hurted somewhere that she won't be nice with me. I met her coincidently and I also didn't start any conversation this time. I just said hi and left the place after I was done with billing items. But later I felt I should have still talked. I am still feeling bad for that scene. But how long am I going to be nice. She should also show some positivity. So I didn't talk this time. I know this is very simple issue. But it was still bothering me for some hours. I will be more than happy to talk with her but if she shows some interest. Please let me know how should I dealt with this.