So sorry to hear this.....it's ok to ramble and be upset....I remember some of your old posts and know how much Tessa meant to you....
It sounds to me as if she had hemangiosarcoma...they often have episodes like you describe, when there is a small bleed and then recover....I know of quite a few dogs recently with this same history - one vet even diagonsed constipation on a dog 2 or 3 times when it was hemangio on a friends dog.....when this started happening to Kougar last spring, I knew what was going on, and after a 2 day spell and then he started to feel better, I let him go, knowing a more major bleed was imminent. His mother, grandmother, litter sister, half brother and a slew of other related dogs had hemangio.... another friend and board member just lost a 15 year old and it was probably a similar thing. but there is NOTHING you can do for hemangio....nothing! Do not beat yourself up!
Take comfort in knowing it is not a painful end, it is just tiredness and lethargy....they go quietly and she was where she wanted to be - by your side....
Csabre Sch1, Hexe Sch2, SG Bengal, Komet, Kira HGH & Kougar v Wolfstraum ~ Ziberia BH ~ ATB Danger Sch1 RH SAR ~ Kougar Sch3, Kyra Sch3, Cito Sch2, Alice Sch1, Kelsey CD, Ret ~ Basha & Fenja Sch3s