Had my period last month normal, this month extremely light spotting only on tampon. could i be pregnant? no sexual activity since before last period

Probably not: One cannot get pregnant if one does not have sex after having a normal, regular period. That is because the uterus sheds its lining during a normal, regular period... and therefore there is no pregnancy at that time. In order to start a new pregnancy the natural way, a woman has to get new sperm into her body. If the prior period was "weird", she can check a urine preg. test >3 weeks after sex.