Hey there Negar! Try not to worry too much about what your levels are at. When I was about 6 or 7 wks I started spotting so my doctor sent me for blood work. I had to go 2 days in a row. The second day my levels actually dropped. This made my doctor think that I was going to have a mc so she sent me for blood work one more time and to everyone's surprise my levels went up quite a lot actually. I also went for an ultrasound at this time and the baby had a nice strong heartbeat and everything seemed ok. I am 10 wks now I still have spotting but I am staying really positive and trying to remember that everything happens for a reason.
So try not to freak out too much and keep in mind that it is still early so give your body a chance to really start producing hcg.
Also this is my third pregnancy (I have 2 children) and I didn't really have morning sickness for any of them. I was just really sensitive to smells.
So Good luck to you and if you have any questions please feel free to ask.