I think i was caught masturbating? did she believe my story?

this happened a long time ago but i just can't seem to stop thinking about it. i know this is weird but i was masturbating in my room one day and all of the sudden, my mom knocked on the door really quick and walked in. before she got in, i went to stand up but my pants were still down. i told her i was changing my pad because it was my time of the month. and i actually do that too. she knows that i always change my pad standing up in my room and i've been doing that since i was young so it wouldn't have seemed odd for her not to believe me. but i'm not sure if she did. Right after, I asked her for extra pads because I was about to run out. even before this incident, she's asked me questions about masturbation and sex so idk if she believes my story or not. also a month ago, she saw a food stain on my bed and joked about it saying "idk what you're doing in here and i don't want to know what that is." i'm starting to feel really uncomfortable now :/ help