PLEASE HELP IDK WHAT IT IS

So i got out of the shower and I stuck my finger up my vag just to make sure everything was okay and right when i stuck it in there i felt a lumpy type ball and i figured it was my g spot but it is right there at the opening of my vagina? It feels like my g spot but I didnt think it could be right there at the opening of my vagina. I can barely stick my finger up there and feel it . i am so scared it could be something serious. it's never been like that before. the last time I had sex was Friday 12/11 if that may help anyone figure out what is going on. I'm so scared what could this be?!