Confused by a girl

I’ve dated this girl for 5 years or so and before then we were absolute best friends and were always very close. We talked all the time all day every day. This fall we broke up mostly because work/life just pulled us apart and too many old arguments kept surfacing. I’m sure we each made mistakes and I’ve admitted mine. Trouble is, we’ve kept in touch and some days we will talk a bunch and others it’s like I don’t exist. The variability is very confusing. When we talk it’s not awkward, it’s fluid like it used to be. When she doesn’t it’s just very odd it just breaks off kinda cold like. I’m having trouble rationalizing what could possibly be going on. I could understand either extreme but why is it so variable. Any thoughts on what I should take from this?

There are a few reasons that this could be happening. Rather than putting possibilities into your head, I will recommend that you talk to her about this.