My Dog Is 13 Years Old Has CHF Now For

My dog is 13 years old has CHF now for about 8 months the vet said about 6 weeks ago she is in palliative care stage now. During the day she is not too bad but at night she struggles to breath . She is on 3 lots of meds twice a day maximum dosage now. Has lost a lot of weight and then put some back on but I think it's fluid . I just don't want to be selfish and keep her alive for me ...and I think she still has some quality of life as during the day she will run outside and bark etc but then start coughing of course but at night I feel for her when she is struggling to breath....what should I do. I have to get some more vetmedin tabs in the next couple of days as she is nearly out again, I need help to decide what's the best.
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