Hi,
Welcome to ehealthforum,
It is difficult to comment on the cause for the mild spotting and the absent/delayed periods that you describe without examining you and going ahead with further evaluation. Implantation bleed usually occurs within 6-12 days of ovulation/fruitful intercourse. The spotting could suggest possible breakthrough bleeding, ovulation bleed, hormonal imbalances etc. Consider visiting your doctor/gynecologist at the earliest for further evaluation if you suspect chances of pregnancy, infective causes, hormonal imbalances etc. Get started on treatment as indicated by examination findings and investigation results. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle. If infective cause is detected, get your partner also treated simultaneously to prevent chances of re-infection, and avoid having intercourse while being on treatment.
Take care.