

My year old cockatiel died under a month ago
I'm going to apologise earlier, this will unfortunately be me ranting a whole lot so just a fellow warning...
I already had another cockatiel (male) in the house. My family and I wanted to give him a friend since he would be alone during the day while everyone was at work/school. That's when we met our little girl, Coco. She was about 3 months old when we got her (the first pic is when we got her initially as for the second is a more recent picture). We don't know when exactly Coco died but it was somewhere during the late night. During the day, she showed no signs. She was singing happily, bobbing her head and dancing as normal. My last moment of bonding with her was when I gave her a shower and she got so relaxed that she took a little nap on my chest. Also, to be honest, I am not entirely sure Coco is a girl. I'm sure she is because appearance-wise, she has the barring/stripes that female cockatiels have on their tail, but she is also unusually good at singing which I have heard is something males typically do. It's not even just a little big of singing, she was just as good at singing as my male and loved to do it constantly. If she is actually a girl, then she definitely is a unique one for sure.
I also wasn't close with Coco initially, she actually liked my brother more than me and it really got on my nerves since I was the main caretaker of the birds. She would get so excited and start calling out just by the sound of the front door opening because she would think its him. She loved him so much that she recognised all his little sounds like something as small as a sneeze and would immediately start calling for him. She loved to snuggle into his shirt, follow him around, and she only ever really listened to him. She listened to me, but I wouldn't say nearly as much as with my brother. I guess one thing I hated most about the timing of her death is that it was right after I actually started to develop a closer relationship with her. It makes me wonder how much closer I could've gotten with her had she not died so soon.
Anyways, I guess something I got out of my first bird death experience is extreme paranoia. I am constantly worried that my male cockatiel might end up like Coco. We did take him to the vet right after her death and he was healthy. That still doesn't ease my anxiety though, I check on him throughout the night. I'm even thinking of installing a baby monitor so I can watch over him properly. What scares me most is that because we don't know how Coco died it could mean she was either sick with something we didn't know of or she had an accident (she was quite timid and more prone to night frights). I didn't expect for one of my birds to die so soon, I know its always unexpected but it feels so unfair that we didn't even have her for that long. I am kind of at a point where I do not want to really get another bird but I am going to just for the sake of keeping my other cockatiel company. I always knew how insanely fragile birds are, but maybe I didn't truly understand the extent of it until one died under my care. It makes me wonder what I did wrong and if something like this will happen again. Do birds really die this easily? How are their birds that survive from being neglected/abused by owners yet mine who had neither of those still died? I'm glad my bird at least died in a home she was actually happy in and very loved by but I still can't help but feel so heartbroken.
also sorry if there's a lot of grammatical errors, I am writing this late at night so I'm kind of half-thinking while typing