Sweetie, you are not stupid for POAS early. We have all done it and we have all been sorry afterwards. No one said this wouldn't be a long and horribly frustrating (not to mention disappointing) journey. All you can do is keep trying, keep POAS, and keep crying when it's not the results you want. I know you are missing Katrina with all of your heart right now, but ask yourself this- Would you want to get pregnant knowing that your cycle is a little wacky right now or would you rather wait until you know your hormone levels are good and you are going to be able to carry a healthy pregnancy?? The only thing worse than a BFN right now is to get pregnant when your body wasn't ready

Looking back, I realize that my first two cycles (directly after my loss and the Jan/Feb cycle) were not normal for me. But my Feb/Mar cycle was much more in line with what I have always experienced- that was all it took. Apparently my body was finally ready to get pregnant again. Now I think that I would have worried myself even more than I am now if I had realized that my hormone levels weren't quite where they needed to be.
I am sorry that you are hurting for Katrina. She is always going to be your first little miracle. your life is not going downhill right now, it's just turning in a different direction than you want it to go for this moment. There is something special out there just around the next curve- you just have to hold on for the ride. It's going to be hard but the end will mean more to you than you will have ever imagined.
I will be thinking about you and praying for you. Just don't give up, it's great that you have been able to talk to your mom about everything. We are always here for you too. Cry it out and keep moving forward, that's all you can do right now.
Hugs,
Heather