I’ve never came before... I don’t think I can!!! HELP

How do you even know if you came or not ?????! I don’t think I’ve EVER came ... I always feel like I’m about to when I rub on my clit but then I can’t ever keep going because my body will tense up and start shaking like is that me cumming? Because I don’t think it is ☹️. I just want to cum ! Idek if I’ve ever came while fucking like this is so stupid I always have to fake because I don’t want to feel dumb