I don't know if I can trust her

My ex is back in my life and im just getting over a heroin addiction she said that she wants to be there for me but she also says she cant handle it when stuff gets bad. She keeps tellin me she loves me and that im her world but I seem to come second in every situation like her friends mom got sick and she decided to stay with her instead of going with me to my counsling. And when I got out early she was shopping with her and she said that she felt better I don’t know if im just perinoid or if shes lieing to me. She did this many different times like she said she went to talk to her cousin when I went to go do a methadone script and she was smokin weed instead of seein her cousin. so my question is does anyone think that she wants to be in my life or if she is just pretending to care for me on.