Confirmed chemical miscarriage 7 weeks ago but have not had a menstrual cycle since, took 1 pregnancy test, negative Could I be pregnant?

Most likely NO. After a miscarriage, or biochemical pregnancy, it is best to wait a couple of months before trying again. It may be that your hormones are not in balance that is why your period is delayed. This can happen after a miscarriage. Hormones can be out of balance from the stress of having a miscarriage. So, please calm yourself and see a doctor.