already had my period for this month, why...

Hello Lottie,
Welcome to ehealthforum,
The second bleeding that you describe, if lighter, could indicate possibility of implantation bleeding (if you had been sexually active and got pregnant). The second time bleeding you experienced could also be due to hormonal imbalance or breakthrough bleeding. Look out for development of any other new symptoms if pregnancy is suspected. If pregnancy is suspected, or if you miss your periods, or if you have abnormal periods, or if periods do not start within 10 days of expected period dates, consider visiting your doctor/gynecologist at the earliest for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). If pregnancy gets ruled out, further evaluation would be done to look for the underlying cause for your abnormal bleeding/periods. Treatment as appropriate (based on examination findings and investigations results) would be started to help you regulate your periods. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Take adequate rest. Drink plenty of water. Maintain healthy diet and lifestyle.
Take care.