really strange my gf is happier to talk to a stranger than to me via text

So over the weekend we had an awkward moment after sex with a slight emotional breakdown from her about us but swore it was just so unreal etc. She made it clear she doesn't want a break.

She knew I was gonna get a new phone. Yesterday my phone card ended and I wanted to wait to get a new phone later after work. All day I guess I obsessed with how she would be so sad that she couldn't talk to men I envisioned her being sad because her bfs phone was dead. I went and got a new phone with a new phone number. I was giddy to mess with her via text. I tested her acting goofy pretending that I had the wrong number but kept texting. At first she was saying don't text me again etc. Then I got a lol out of her. I then was like where are you from and she told me. I said I lived in the area too. She seemed excited to be talking to a new guy. I didn't get super weird just mostly gibberish. But I was weirded out how she insisted at times to keep the conversation going. I got her to lol 2 or 3 times. At this point I was the last thing on her mind. The bf she hadn't talked to all day.....Then I confessed it was me and I felt the magic die. She goes "oh". Then her next response was "good times". The conversation died when she realised it was her own bfs she was talking to. It took her at least 15 minutes to get back on track and start talking fine to me.

I dunno just odd right? Why is a woman sending lol's to complete strangers?