Sis, please see your OB as soon as you can para ma-check properly, any changes sa period mo deserve professional eyes, and they can tell you exactly kung safe ang combo ng melatonin at pills for your specific situation. Hindi ko yan pwedeng sagutin confidently kasi medical talaga ito!
A few of us moms have taken melatonin while on BC at hindi naman naging issue, but honestly everyone's different, your doctor lang ang makakasabi ng tama for you. The spotting you had is worth asking them about rin, kaya go na sa OB, ha? Don't stress too much while waiting to see them, maraming reasons yan pwedeng mangyari, pero better peace of mind from your doc. Sending you a hug!