Calia,
This is terrible that you have to relive this again in such a short time. It's not fair for any little one to have to go through this.
As I read this is sounds more and more like what happened to my little Erin. She passed after a few weeks of having her too. Did either of them have a swollen belly or realyl strained to go to the bathroom before it was too late?? We had it confirmed after Erin passed because we wanted an autopsy done... she had F.I.P. It's a common yet not so common illness that can get the best of them. Some just get sick and bounce back from it and others like my Erin ended up losing the battle. Maybe check up on that and the Corona Virus. If you got your little ones from shelters... it raises these diseases more common.
Oh honey, I wish I could give you a big hug right now. Losing a little one is never fun because they truly are your babies.