Extra session can be very helpful, or not. It really depends I think. You should never ever feel guilty for wanting, or asking for one - ever.

Your therapist may suggest a phone session, or simply want to discuss with you over the phone what is going on.

Whatever the case, I would definitely make the call and reach for help. It can stop a spiral, or at least give hope that things are going to get better.

Extra session can really be good so your therapist can see what a crisis looks like for you, and what may trigger or compound one.

Again, definitely make the call.