I'm so sorry, Jallen. A sudden loss like your Franklin feels just devastating! I'm so sorry he became ill and declined so rapidly.
We all second guess ourselves when we have to put a beloved pet down. But it certainly sounds like you had no choice but to relieve his suffering. You relied on the expertise of your vet and they have a good sense of what can't be survived and of when it's time to let go, wretched as that is. It's the hardest decision, ever, and the most painful. My heart hurts as I read your post, knowing how broken your heart is. I wish you comfort today, and for you to know you did all you could for your guy. All this is a terrible thing to have to go through. Be gentle with yourself, cry all you need to, write here, talk to friends. Whatever it takes to get through this sad time. It takes real time to recover. Thinking of you this morning.
-Missing Marissa deeply