It is so good to see you here. I am sorry I missed your post the other day.
Both depression and anxiety can cause a kind of “brain fog” that makes it difficult to concentrate and pay attention to things. As a result, it is harder for depressed or anxious people to store information in short term memory.
Yes your anxiety can cause the short term memory loss. The garbled speech also can be anxiety or as in my daughter's case after doing EEGs etc, it was decided she had an atypical migraine as she was at a wedding and had a headache and then her speech become garbled. She was aware of the speech as you are.
I would really work with your physician if you have fears of a tumor and let him know your concerns.
I am here for you so please keep posting as you are family here.
Hugs to you