Hello,
Welcome to ehealthforum and thanks for writing
If you had unprotected intercourse in the past then the spotting/light bleeding might be indicative of implantation bleeding which is an early pregnancy symptom.You also have missed the periods in a row so it is more indicative of conception.
Miscarriage usually presents with heavy or intermittent bleeding with occasional passage of clots and crmaps.It requires a pelvic examination and USG scan to rule out the cause.Kindly visit a Gynaecologist for evaluation.
Take care!