After the sudden death of our cat yesterday, I am torn between getting another within a shorter time or?

I can not even describe how miserable and terrible I feel over the loss of my cat Rascal. He was not even 3 and over less then 36 hours developed a blocked urinary tract and died. I have never had a cat with the condition and due to his personality and just daily cirstances we really had no way to know he was so sick until we were rushing him to the vet last night; where he was too ill to be saved. I got him as a valentines gift when I was pregnant with our now 2 YO. My husband reluctantly got him for me (I've literally ALWAYS had at least 1 cat) he has never before had one; but always had a dog. I am currently pregnant with our second baby, so my husband has been bearing the rbunt of the litter duty (which I can admit I always put on him even though I swore I'd do it). Anyway, he was a rescue cat and I almost feel the best way to fill the void is to rescue another. Our shelter is a kill shelter so I would feel much better getting one from there as I would be saving a life in a way. Even our 2 YO chocolate lab is obviously sad/depressed without our cat around; and it hasn't even been a day yet! I certainly am not going to go out today and get another. But I am somewhat torn between whether to get another sooner or later. For me to heal I feel that sooner is better. However being as my husband isn't a "cat" person, and although he is heartbroken; he would never get another if I didn't want one. I am just thinking that it may be easier to get another cat now and have it litter trained before the new baby arrives. As opposed to waiting 6+ months and then having to take care of 2 kids and litter train a cat and get it used to all the kids ect. ANy suggestions? I deffinatly will be wanting another within the year. And like I said I want it to be a rescue so that way lossing Rscal sort of has a purpose in a way.