I would read that as "BTW it's fine to text me" as in no need to apologise.

In my experience it's very helpful to have an explicit discussion about contact outside of sessions. Maybe you could have that conversation in your next session? I was lucky when we first talked about it because my T brought it up. It is useful I think to clarify these things, and also to feel comfortable asking T to clarify what they mean if it's not clear.