keeping you in my thoughts and prayers.. I hope everything is ok!
Take care of yourself
XXOO
I hate ultrasounds at 6 weeks for just this reason. For some, a heartbeat is seen, for others, not until later. It can even depend on the quality of equipment and the skill of the tech.
Cramping is pretty normal. In all honesty, with all my miscarriages, the symptoms started with bleeding, not cramping. The cramping didn't come until the bleeding was getting heavier and I was getting ready to pass the tissue. At this point only a follow up ultrasound will really give you answers. Do not expect the HCG levels to rise significantly when they are at 27000, and only a 24 hour time frame in between. It may quite a minimal rise. HCG levels are just not an accurate way to see what is happening at this stage (unless they are dropping significantly). But another u/s in a week should give you your answers.
Good luck, and I hope all is well.
I wouldn't worry unless you see bleeding. Its normal for some women to have cramping in the beginning. I did. Six weeks is still too early to detect much, i know its difficult, but give it some time and you will see your baby soon! You are doing the right thing by continuously getting checked out! Don't feel like you are overdoing it. Its ok to be concerned.