symptoms like mood swing, nausea, loss of weight.

Hi,
Welcome to ehealthforum,
If you are pregnant, it is possible that you had decidual bleeding. Few women experience period like bleeding during their expected period time during first few months of pregnancy which is also known as Decidual bleeding. If the symptoms suggestive of pregnancy are persistent, you should consider visiting your doctor/gynecologist for further evaluation. If pregnancy gets confirmed, an ultrasound scan done will help to know the gestational age and viability, and a serial HCG level test done showing doubling up of the hormone levels in 48-72 hours to show that pregnancy is going on smoothly. If levels are not adequate, then external hormonal supplements would be considered to be started to help you in preventing miscarriage. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately.
Take care.