Please Help 😩😩😩😩😩

My prom is on Thursday.... I had my period twice in February so I thought my period wouldn’t come on in March because that has happened before... I was going to get birth control on Saturday but my mom told me I needed to get a Pap smear first so those plans were canceled ... but it came on Monday morning and now I’m very upset.... help me please, I want to be able to enjoy prom without any hassles. Anyone????