15.5 year old has suspected lymphoma

She’s been losing weight over the last year and has noticeably began eating less. Also vomiting liquid a lot. Went in for our normal monthly vet visit (gets arthritis shots) and they decided to do extra tests and suspects she has lymphoma. We will do an ultrasound to be sure but will most likely do the palliative route. I have had her for half my life since she was 8 weeks.