I've learnt from my long experience that, as John Lennon says in 'Beautiful Boy', "Life is what happens to you while you're busy making other plans".
I've always tried to overplan my life, but things have so often not turned out as I expected - and often it's worked out better than if things had gone according to my master plan.
Also, I'm the mother of an only child. Parents who intend only to have the one offspring - often because they feel that whilst one is copeable with, a second would disrupt their life - have cited me and my now grown-up son as a good model, because he is charming, sociable and has done well for himself.
But this only-child situation came about less through choice than by accident, and there is hardly a day when I don't find myself wishing that I'd had another child. For his sake as well as my own - I have three sisters and though we still argue after all these years I'm very glad they're there for me when I need them. I don't contradict the parents who've used me as a good example because they've already made their decision, but I feel like begging them to have another one because they'll only regret it.
It seems to me that if you and your DH were intending to have another baby it might make sense to go ahead and embrace this pregnancy, as you put it. You're making the assumption that at some future date when you are 'ready' you will be able to conceive a child without any problem, and it does seem likely since you've become pregant easily enough now. However, it's never 100% certain that it will all be plain sailing.
But this is just my take on the situation. As other posters have pointed out, you still have some time to get over the unexpectedness of the news and get to the bottom of how you really feel.