Going behind Mum’s back??

So I was supposed to get my period today(ish) and still haven’t. I have my year 12 camp on Monday (its Thursday night) and we’ll be doing water activities.

I haven’t ever tried a tampon yet though I know I should, but I’d rather just skip my period.

The thing is, my mum doesn’t want me to go on the pill ever, but today my friend said that she would give me some of hers to stop my period before camp and start it back up when we get home.

Should I take the pills without telling mum, so I don’t have to worry about my period on camp? Should I tell my mum? Should I just try a tampon...??? Will the pills screw me up?? Pls help x