My girlfriend lie to me or don't be honest

So i am in a long distance relationship since 9 months so few days ago late at night 12 we said good night to each other on text and i closed my texting application and just was going through other apps for any notifications or messages like insta and discord so their is this discord sver ver of mu friend its big me and my gf we both are in it so yeah that day i was checking the server before going to sleep and i saw her in a voice channel so basically in discord you have voice channel where peeps of server can join ans talk so yeah she was ther and her mic was on i was able to only see that i didn't enter the channel so yeah and their was only 1 guy in that channel with her i didn't suspect much coz i thought might be her some friend so next day she woke up late so i just assumed in my mind that she might have slept late so yeha obviously so she woke up late so i ask her why ao late i mean did you sleep late or something she said yes and i asked her why then she said she didn't felt like sleeping and was doing math (she is a university student like me) so yeah i was just shocked coz i saw her talking and her mic was on so yeah i am just confused why did she lie btw i didn't told her that i saw her in voice channel so yeah i just need to know what should i do now should i just chill or what

seems like shes covering something up talk to her abt it