I breed, so I get asked this a lot by prospective buyers and I have seen both 'sides' - the people who are ready and it's 'their' breed and the people who 'aren't.
I have one buyer, who has been buying from the 'Kennel' for 30 years - she bought her first Goldie puppy from my mum thirty years ago. She bought her latest dog from me only about a month ago. She always has 2-3 dogs, and she always says the best way for her to 'manage' the possible grief (and guilt) is to alternate girl and boy. She doesn't view it as replacing the dog she lost - and how could it be because each dog is so individual - but she is aware of the possibility the lines might 'blur', and so she never gets the same 'sex' back to back.
I have another buyer who does the same- boy, girl, boy, girl. He never has more than one at a time, and he always alternates and likewise he used to buy from my mum when she bred. He finds it easier to buy the same breed. He absolutely is still grieving the dog he has just lost when he comes to meet his 'new' puppy - and I don't judge him for it. We all heal in different ways and, for some, a new puppy of the same breed helps with closure.
Other prospective buyers have approached me and they've even managed to make it to being allowed to meet a litter (one was even on my waitlist for a year!)...and then they've realised it's not right and they're not ready for either a dog or, simply just that breed. And that's okay. Until that puppy is in your arms you cannot know if you are ready or if it's right.
What is right for some people won't be right for others. I think it's a very individual choice. The worst thing that can happen if you go to view a litter is you realise you're not ready and, I cannot stress this enough, no good breeder will ever judge you for that - so please don't be afraid to start putting feelers out there if that is what you want to do.
I am so sorry for your loss though - saying goodbye is awful, but when you've had them so long it is like losing a part of yourself.