It may be to early. Just relax and have faith! You could be thinking something is wrong because of last time, but everything could be ok. :D
how far along where you on the first ultrasound and on the second ultrasound, and what did you see in both of them.
Sorry you are going through this. You should tell your doctor you want answers. It could be just a horrible coincidence, or it could be something off that could be fixed easily (like a hormone embalance). Sorry for your loss!