To feel left out?

[UpsyDoosie]

Asked Dsis1 if she wanted to start going walking in local park. She said yes, once her DD was feeling better as she was ill.

Yesterday (a week later) I talked to Dsis2 who said that she had gone walking round park with Dsis1 and they were making it a regular weekly.

AIBU to feel hurt?
:(

Nooo they’re your sisters! Just tell them you’re coming.

Just tell them your going to.

Invite yourself

They are your sister's, surely you would just say oh I'll come with you next week on your walk.

Just go with and don’t make it a thing.

Is this a pattern of behaviour with there being 3 of you OP, ie 2's company, 3's a crowd? If not, then just ask what time they go and tell them you'd like to join them next time. Although it does seem a bit weird that you mentioned the idea to one of them, and seemingly they mentioned it to the other who also wanted to do it, but then didn't let you know or ask you to join them.