I would agree with you that you have reason to be concerned.
Therapeutic boundaries are essential to therapy, as in without them the engagement with the therapist not only does not accomplish the healing you come to attain, you are actually harmed instead.
Boundaries do not necessarily have to be specific rules (therapists do vary on their boundaries about all sorts of things from physical contact to how they handle communication outside of session). Also, boundaries can be flexible depending on the client’s actual needs.
That said, the boundaries do have to be consistent, especially when specific expectations have been set including the session length. It’s not that it’s not OK to change the session length, it’s that it’s not OK to change it randomly or arbitrarily without having a new conversation where the change is discussed and the new expectations are communicated.
To take session length as an example, if you are expecting a fifty minute session, that’s what you should get. It’s probably fine if it runs over by five minutes, but you should not suddenly get a two hour session. There are situations in which a two hour session would be beneficial and in that case the therapist and the client would have a conversation about having a two hour session either as a one time thing or as a regular thing moving forward. My therapist and I recently made that decision about my therapy. The important thing is the intentionality. You as the client should understand the reasons for the change and agree to it ahead of time.
The deal about you can reach out any time is an example where you were told by the therapist that there’s a new expectation. However, if you have reservations about it or what it actually means, then you should definitely bring those up. You have to understand what the expectations are moving forward and agree to them. The therapist can initiate a change, but the client has to accept it.
A therapist telling personal stories is not intrinsically a bad thing as long as her doing so is truly helpful to the client. Same with her communicating that she enjoys talking to you. What makes such things unhealthy is if they are either excessive, unhelpful to you, or if the therapist is in any way looking to you as the client to meet her own needs.
If you feel uneasy about these things, for sure trust your gut and at least bring them up with her and have an honest conversation about it. If you still feel unsafe after the conversation, then you may have some other decisions to make, but it’s good to give the therapist a chance to explain her thought process and how she believes the changes she has proposed will help your treatment move forward. Then you can look up what she tells you to see if other therapists have done the same with good results.