Hi Babyblue,
I'm sorry to hear that your clinic have not been very helpful by not explaining anything to you - I hope you will be OK with my answer, I don't want to scare you. And sorry for butting in on the nurses thread.
First thing you have to remember is that everyone is different and what may apply to others may not apply to you. Also, you have definitely managed to get pg, which is a good sign, it is just what happens next.
There are three explanations to your results (and why the clinic asked if your af had arrived), and unfortunately none may become clear for some time.
The first is that you are a low hCG producer - this does not mean that your pg will not progress as normal. (I am in this category, my 1st tests for this pg were pretty faint too and it had me paniced)
Secondly could be an ectopic as hCG levels will tend to be less than in a normal pg (Again, I've experienced this BUT I had lots of pain and nasty bleeding - and looked a positive mess)
Thirdly that you have had some implantation but a very early miscarriage (also referred to as a chemical pg - I've had this too on my natural pg)
The most likely answer is the first - the second and third are rarer cases, especially if you have had no bleeding. I understand it leaves you in limbo for some time (having been there myself) but you just have to try not to get too upset about it until you know what is happening as if you are in the first case all that upset would have been for nothing.
I would suggest hanging fire for about 4 days before doing a home pg test again (remember to do it the first pee of the day for it to give an accurate result)
Sending you lots and lots of cyber hugs

, its not a nice situation to be in - I've got my fingers crossed that everything works out for you.
I'm probably going to be on chat later tomorrow (about 3-ish maybe - not totally sure of the time yet), so if you make it again, we can chat more
until then - lots of love Fiona xxxx