My current T I started seeing when I was 16. She got pregnant the first time and I felt the same way you do. It hurt and she was gone on maternity leave for so long. I waited for her though. Then we worked together for a few months and she developed a serious health issue and was in the hospital for a month and out of work for 9 months. That was hard. I refused to see anyone else because I only want my T. Then when she came back from her medical leave she was pregnant again a couple months later. I was devastated that we would have yet another break. I quit therapy for a few years. I started seeing her again a little less than two years ago and it was one of the best choices I have made.
Your feelings are normal and you can see her when she comes back from her maternity leave if you want. Its worth it if you like her and you like working with her. I also think you should talk to her about all of your feelings right now and process them together. Maybe she can help you with your anxiety and feeling so alone. I wish you the best and good luck.