Mom found my condom in the bag

I'm 24(M) and I have a girlfriend, no relative of mine knows about my relationship as we are conservative family. I had bought a condom and hid it in my bag. I just came back from my female friend's marriage. I went with 1 male friend and 3 female friend. It was a 3 day trip. I came back but i forgot to remove the condom from my bag and i understand mom had went through the bag and took it because its not there now where i kept it. She hasn't talked to me normally till now and neither confronted me. She asked me about the three female frnds i went with. I think she assumes i had sex at my friend's marraige with my female frnd.I dont know what reasoning should i give her as i wanna keep my relationship secret.