I can't shake off the coldness and doubts in my long-distance relationship

I've been unable to see my girlfriend for two months because she's very busy with work, but she recently started following a girl on social media. When I asked her about it, she brushed it off by saying it's just a coworker. I don't know, it feels like there's something really off, like she's hiding something from me. Honestly, the old intimacy we had is gone too. Do you think I'm just paranoid, or is this kid really up to something?