It's good to hear from you!
It sounds like you have tried to communicate your feelings to your therapist about the shortened appointments and doing other things while you are there and she has not addressed it. And you are left feeling that you are not important.
What may help you is to figure out what you feel you need from your therapist. What can she do to make you feel more important? Let her know what you come up with.
Also, do you feel that your needs are about what she is not doing, or about unmet needs you have from your past? It could also be a combination of the two. Sometimes people will transfer feelings in therapy to their therapists that are unfulfilled from their childhoods. Given that your therapist is cutting your sessions short, it is unlikely to be all about transference, but it doesn't hurt to look at it just in case.
In between your sessions, it may help to rely on other sources of support. Learning more about depression and PTSD can help. Understanding your symptoms better and learning that what you feel is normal can go a long way to make you feel better. Also, support groups can help. Talking over how you feel with others who experience the same symptoms is very helpful. And keeping yourself busy. Makes plans to go out everyday to do something. Give yourself something to look forward to on the weekends, like taking in a movie or going out to dinner. That way, the time goes faster between appointments.