I am so terribly sorry for your loss, truly.
I lost my puppy on Jan 14th after 15 years together. I'd had her since she was 4 months old. She was my sole purpose for living when I was a teenager. We grew up together in an abusive situation and the horrible thought of her being left alone there was the only thing that kept me alive.
Don't feel like your wrong or weird to not want to tell people. I didn't tell anyone other than my grandma and my mom for over 3 weeks. And I spent 2 of those weeks just sitting and staring at the wall, or laying in bed and staring at the ceiling, and crying. So much crying. And shrieking and screaming, I just fucking lost it. I cried and screamed for 2 fucking weeks until it literally made my face and body hurt. During the odd moments I wasn't crying, I most certainly didn't want people to bring it up and make me cry more. I'm very glad I kept it to myself until I had semi regained sanity because when people found out and started trying to talk to me about it, it was HARD. I could not have handled people's prying those first couple weeks. We all grieve differently, so there is nothing wrong with you keeping it to yourself until your ready.
I understand that you blame yourself. I blame myself alot for my puppy too. I mean I know she was old at 15, but I can't help but feel that if I had done better I could have had her a few more months. She had mast cell cancer. After a failed surgery, the vet said there was nothing more she could do and ignored my calls for 3 months. I finally went to a different vet and got another opinion and was told there are most certainly other options to try. I can't help but feel if I had gotten that second opinion sooner and been able to start her on palladia sooner, I might have had a few more months with her. I'm sorry you feel guilty too. I have no sage words of wisdom or encouragement, other than to say that your not suffering alone and I hope that brings you some comfort.
It's been a few days since your post, but I do hope you weren't too rash about deciding on what to do with your other guinea pig. During high stress tines like that, sometimes we make hasty decisions we later regret. We have another dog, he is 7, and he's always had my dog. He's never been alone. He was alone for 2 weeks, and seemed very sad. We decided to rescue a puppy so he would have a friend. I got a new puppy, not for me, but for him. To be honest, and please don't hate me or think less of me, I was almost resentful of the new puppy. I didnt want a new dog, i already had a dog, the best dog, and i didnt want a new one. I had a mental breakdown. I even begged my husband to return her to the shelter. I just couldn't handle my feelings and emotions, and taking care of a new puppy, and I was also sick and exhausted with covid. After I got over that breakdown, then I felt guilty because she is such a happy and sweet little girl but yet I didn't love her like I love my ol dog. I did enjoy that my other dog was happy to have a friend to play with again, and that's what I focused on.
It's been a couple weeks now. I still don't love her like I loved my sweet Ellie, but I do love her. I don't feel resentful anymore. I'm glad to have her now. Honestly, as cold as it sounds, she's been a good distraction. It's hard to just sit in one spot and cry for hours when you have a puppy that requires you to constantly watch them and keep out of trouble. She is what, albeit begrudgingly, got me up and moving and functioning again. If my husband had let me return her to the rescue, I would have regretted it. If you truly feel like you don't have it in you to care for your other guinea pig, then I totally understand finding it a new home. I didn't feel like I had it in me to care for and love my new puppy either. I found it entirely too overwhelming. Just make sure your certain before you make a decision you regret. Maybe you can do like me and try to find one at a shelter and get it a friend instead. Getting a shelter dog helped me feel better about getting another one because atleast one thing came of this tragedy, a deaf and unwanted puppy found a home.
I hope your doing better since your post and I hope I didn't say anything to make you feel worse. I just feel so sad for you cause I feel sad too.