Yes, I completely felt like that. Ours was also unplanned but very much wanted, and we had a few days from finding out to knowing that I'd miscarried. I have this feeling of emptiness, I count how many weeks I should have been, how long its been since I found out, etc.
I also sit and think about all the things I did wrong when I didn't know I was pregnant and for a few weeks, and still occasionally I am 100% convinced that I am the reason we're going through this pain. But, I had a good long chat with my GP and she said that honestly, there's nothing I, nor anyone else could have done to change the outcome of this pregnancy, despite everything our minds tell us, there's nothing that we could have done, or should have done that would change it, and it's an awful fact but just know that it is not your fault it happened, it's no ones fault and its cruel, and unfair.
Take care of yourself, if you don't think you can go to work then see if you can take a few days, give yourself sometime to process and grieve for your loss, try your best to stop beating yourself up, but I know that feels almost impossible, but it isn't your fault.
I'm so sorry for your loss xxx