Internet friends

Okay so there is this girl I’ve been talking to for 3 years now nonstop. Like we talk everyday. We text all the time. In my real life I wouldn’t say I’m lonely 24/7 but most of the time I am so she’s my main company. The past week we haven’t been texting much because she was busy and I caught myself feeling anxious when she takes too long to text back (like hours). Like I get anxious that she may be sick of me or she will come back and tell me that she doesn’t want to text anymore or that she just doesn’t care. And i keep checking my phone to see if she’s replied. Of course I didn’t tell her anything but I want to stop feeling like that. I don’t like the idea of being addicted on my phone and her as well. I understand that she’s busy I am too sometimes and may not text her back for longer but I don’t know why my mind feels like that. Please if anyone has any advice on how to chill my mind and deal with the attacks im getting..