I am so, so sorry.
We lost my boy last year in a very similar way and it is such a trauma and shock that it takes time to get over.
My boy was only 7, but had been ill for a couple of years. He had already had a TIA a few weeks earlier, but made a full recovery, although we were warned he could go on to have a full ischemic stroke at some point. It still came as a terrible shock, as he had been doing so much better over the previous weeks and it presented very differently. He had had a good day, sleeping in the sun in the garden while dh worked out there. Dh was sleeping downstairs with him, because he’d had some digestive issues and often needed to go out at short notice, so he was sleeping on dh’s legs on the sofa when at 6.00 am he suddenly started breathing strangely and his eyes became sort of fixed, dh called me, I shot downstairs and sat holding his head and talking gently to him with dh next to us, but it was clear he had already gone, his heart carried on for a short while, with the gasps as you describe, then it all stopped. I was told afterwards the gasps are involuntary and sadly normal in this sort of situation. On speaking to the specialist vets afterwards they were certain it was a massive stroke and reassured me that he won’t have known a thing about it. All he will have known is snoozing with dh, nothing after that.
I was an absolute mess and didn’t sleep much for weeks, but after a while was able to appreciate that the last thing he remembered was snuggling on a blanket with dh and was thankful that he didn’t have to go through the trauma of being pts at the vets without us there (this was during the first lockdown and it was something we had had to consider a few weeks earlier, but decided against). At first I was angry with myself that we hadn’t let him go sooner, but over time I realised his last few weeks were spent being safe, comfortable and happy with his family and his last minutes were actually peaceful and surrounded by love, so in actual fact it was probably the best thing for him, as after lots of treatment over the preceding year, he hated the vets by that point.
We are now in the final days of our 16 year old lad and to be honest, much as I don’t want to lose him, on balance I think I would prefer him to go like our other dog did, rather than in a clinical way at the vets (although we are planning a home visit, as his is a slow decline). I am absolutely dreading it and my heart, which still hasn’t healed, will break all over again.
Please be kind to yourself, you were there with her at the end and she will have felt loved and safe, you couldn’t give her any more than that. Give yourself time to grieve, talk about her when you are ready and gradually the sadness will start to give way to happy memories. It never leaves you, but it does get easier. We are a year and 4 months on now and can talk about our boy and smile and laugh at memories of his antics again. The dc and I often look through his photo album and videos, so his memory is well and truly alive in our household.
Take it at your own pace and you will find your a way through it that feels right for you.
Sending much love and light to you and your family. xx