Light period!!! Help :(

Hi! Can anyone explain to me the difference between spotting and light period? Actually I'm kinda nervous rn cause it's already my second day of having my period and usually my period during this time is heavy but now I kinda have a light one.. I mean not too light.. You can compare my period right now to a "second to the last" day flow. But I have a strong feeling that I'm not pregnant cause me and my husband had sex but he never came inside me. But it kinda bothers me, why do I have a light period as of the moment? Is it normal? Someone please help me. 😭 Would really appreciate it. Thanks!