Need advice, can I trust her? Heartbroken

My girlfriend has displayed severe outbursts of anger of the past 3 months for the smallest of things, and her mobile phone has always been an issue in our relationship, with her answering things as soon as they come in constantly, and basically not being able to leave it alone.

We have been seeing each other on and off exclusive for the 2 years with an actual official relationship since October last year. It took me that long because of my abusive ex-wife. So I know I have trust issues.

During that time I have noticed some red flags. She had a message from a guy November last year which read "Hey, how's it going? Xxx" which was apparently someone from Tinder before we met in October 2016. I find it hard to imagine a guy from 2.2 years ago would message that message after so long? My first doubts.

A previous similar message from August 2018 is now the one she is saying is Tinder, but I know for a fact she said it was the November one, so I feel really hurt being lied too. She didn't reply to either message, but they still made me wonder as she changed her story.

She started to have panic attacks recently and I wonder if it's guilt, she did go through something traumatic but my gut tells me otherwise. Another example of something else not adding up was noticing she was online (WhatsApp/Facebook) an awful lot (like constantly).

I noticed she was on their from 10am until 1.35am which sounds fine, but here is the weird thing. She said she messaged a friend back, and spent loads of time writing a message to her friend she has fallen out with multiple times but didn't send it. When I checked the reply message to the friend was the day before, so I find it hard to believe she was on and off maybe 7-15 times in a day that day without sending a single message? I.e has it been deleted. I feel like she has lied to me, my gut is telling me bad things yet she begged me for 5 hours not to leave, I left it saying I need a 1 month break to get myself back together as this was affecting me along with her very fragile state currently over the last month (she's signed off work). So I guess the question is, if she swears her innocence yet I catch her lying and I love this woman, could this be purely what she says, am I thinking too much into it, or is there more? During our break she was texting a lot of guys and sending selfies, nothing dirty but it made me uncomfortable because if she loved me like she says she does then why would she contact someone at midnight with selfies of her on a night out? It's a work colleague, and she says she was drunk.

Thoughts?