Been dating/exclusive with this girl for four months. Plated her for a long time before it. We became exclusive around October 10th. I believe in trust but verify and looked at her phone recently, in her list of texts around that time the dates go 10/7-10/8-10/18-10/10 so they are out of order, and this text(10/18) was to one of her old fb's. I'm not familiar with iPhone but I think this means the 10/18 message was deleted, as the last message in that convo was 10/9. 10/17 she texted me saying she'll probably be up late as she can't sleep and doesn't wanna keep me up(I had a long day) and that I should probably stay home. She included a period which she never does. She then stopped texting me from 8pm-6am the next day(10/18) apologizing for the gap, and also saying she's getting sick. Idk if this is well known but sometimes when you give oral you can get a sore throat after that feels like you're sick. I feel lost because this happened so long ago, and I'm a paranoid person by nature so it's hard to trust my thoughts on these sorts of things. Not only that, but the relationship has been good otherwise so I'm apprehensive to make a decision based on what happened a week after. Again it's been four months since then. I can only make a decision when I have irrefutable evidence and am 100% sure that something happened. Do yall think she cheated?

Edit: this is what it looks like https://imgur.com/a/4Qn0zHv