Don't give up! Yes it isn't ideal w no growth but you don't know for sure what's going to happen. Try and keep the faith.
Hi - I am in a similar situation to you - I had an US last Friday and the lady said all was looking ok but baby was measuring 5.6 weeks with a 120 hear rate but sac was measuring 7 weeks. She said the only way to know if things will continue to be viable is to wait to weeks and have another us. I went to my doc and she confirmed this so i have had a long wait on my hands. I lost it yesterday and called the us place and they said i could come in Monday for the next us rather than on Thursday so at least i have a few days less to wait but it will be a very long weekend. As for your situation I think it is positive that you have a heatbeat that is increasing and that some babies might just grow at different rates. I can't offer much advice more advice becasue i know there is not much anyone can say because the wating is just horrible - good luck and i hope we both get good news for christmas.
It is great news that the heart rate is picking up.
Sorry to hear the baby is not growing very fast.
At only 6.5 weeks, most drs cant even pick up a heart beat, so that should not be of any concern.
Still very early...babies grow at different stages and they may start out slow and be 10 pounds at birth. So don't give up...keep your head up.
I will keep you in my prayers that everything works out for the best.
Good Luck and congrats on your pregnancy!