Worried...

So yesterday was my first ultrasound at 8 weeks. I was expecting to hear a heart beat. But the doctor told me according to my period I should be 8 weeks. Well according to the sonogram I'm 5 weeks. So the doctor told me it could be two things, either im really only 5 weeks and since my period is irregular that's what confused us or my baby isn't developing how it should 😞. So they took blood out and they should give me a call today with the results. So I'm hoping for good news 🙏🏼. I just can't help not being worried.