Is using a tampon equivalent to losing your virginity (social construct of virginity)?
No it is not. Your tampon does not take away your virginity. Only your first (consensual) sexual experience with someone can do that, and that should be completely at your discretion.
Using a tampon (which is actually considered a medical device) for your period does not change your virginity status.Tampons work equally well for people who have or haven’t had sex. Moreover, using a tampon does not mean you lose your virginity. Even if a tampon stretches your hymen, virginity is related to sexual intercourse and not using tampons.