I am so sorry about the added, and completely idiotic and selfish, layer of pain from STBX. I think most all of us know the feeling of "baby steps" that are pulled out from underneath us. It's so hard. It's like reliving the "bomb" all over again.
Don't feel badly about how you're feeling. You have gone through so much loss in such a short amount of time - 1 month. Of course this is going to rip you up, and devastate you for a bit.
But, remember this. You did this before. You stood up again. You stood strong and took charge. You can do it again. I promise.
We are all here for you. And, we're all examples on this road ahead of you that you CAN make it - strong and happy again.