What should I do about the situation?

My dad and his girlfriend weren't really getting along because of an incident that happened so we don't stay with her anymore and oneday he picked me up from school and she was right in front of his car and I didn't say hi to her because I know she was upset with me after she found out some stuff that I wrote in my diary but I wouldve waved at my lil bros and sisters but I didn't even see em' she txtd me saying I had no reason to be mad and for a while we were texting back and forth and then her daughters started to text me expressing their anger and then his gf sent me a calm txt saying she hopes I'm okay.. I never texted back though and now when I see her daughters at school I act like I don't.. And now when I'm around his gf I dnt talk to her but her & my dad seem to be getting along better it's been 6 days since we texted.. Now I feel horrible I don't know what to do