Sure, there are general guidelines of therapy, but good therapists can allow for flexibility based on the needs of the client. For example, there is a "rule" of therapy that everything needs to stay in the room and outside contact is inappropriate because it breaks the frame. But many therapists -- yours and mine included -- have chosen not to follow that rule with clients who benefit from being able to contact them between sessions. Since your T's situation is changing in a way that is disruptive to you, she is again being flexible about suggesting you see (and attach to) somebody else. That seems like the fair and reasonable thing to do to encourage you to get the support you need. You would be much worse off if she somehow tried to prevent you from getting therapy just because she decided to have a baby. That wouldn't be very fair to you.

I also think you can't know how you'll feel and what the situation will be like in October. I can't tell you how many times I have worried about some imagined stressor way off in the future and then discovered that it wasn't worth worrying about because of some unforeseen circumstance. I know that's easier said than done, but I do think it's worth taking things one day or one week at a time until it all feels less overwhelming.