Im the Overthinker in the relationship and it’s getting bad. 20M and 19F

I 20M have been talking to this girl 19F I knew from work. We worked with each other for like 3 years but was just friends because she had a bf at the time. A year has passed since then and i decided to join the Military and now we’re across the country from each other. About 4 months ago i texted her and we’ve been talking since. We are not official yet but i plan on making it official on new years which she said she’s ready. We already act as if we are official and everything. We’ve also already did everything people in a relationship would.

Since we’ve been talking we’ve seen each other twice. The second time tho… we got drunk and she fell asleep and I got curious so I went thru her phone. Turns out she was texting these other guys from a cruise she went on. Things like “want to meet up at the bar?” “I miss how you made me laugh”. So I got very upset about it and she woke up and asked what’s wrong, I told her and she blocked the guy and told me it’s because she was questioning the long distance but now she’s all in. We’re not official but we act as if we are so she shouldn’t be doing that right? So because she said she was questioning it at the time I took her word.

Ever since that happened I’ve been overthinking like crazy, my anxiety is high. I constantly check her socials and who she’s following. Like today she posted a picture of herself and I was overthinking about “what if the other guys hit on her” it’s obviously okay for her to post what she wants so I can’t be like this. I would talk to her about the overthinking for reassurance but I don’t want to push her away

I really like this girl a lot and want this to work. I think I might ask her if I could go thru her phone one last time when I see her for new years to make sure I can trust her before making it official. This overthinking and anxiety needs to stop. Do yall have any tips leading up to seeing her?