Thanks for your response. I have a checkup today so maybe the doctor will do a beta. I am sure they are at least going down or else the test would have been more than just faint since last beta was 4900. I am definitely not ttc this cycle. My cycles are usually so regular that I am finding it annoying not knowing when to expect it this month. I guess I will just have to be surprised.
The hCG levels in your body stay around for a while after a miscarriage so you may get a positive hpt for a time. You can have your doctor do blood levels (two draws 2-4 days apart to see if they are increasing, as they would with pregnancy)
One reason doctors recommend that you don't try to conceive again for a few cycles after a loss is because it is so hard to date a pregnancy if you haven't had at least one normal period after.
In answer to your question, to the best of my knowledge, CD1 is the day of your loss HOWEVER the first cycle will most likely be wonky and you may not ovulate when you would normally expect to. It is best to wait until you have had at least once regular period after a miscarriage to TTC
Best wishes for you!