cheating :(?

So my partner has done a lot of lying and stuff in the past , with cheating behind my back. This is going back 4 years ago. But she has lied a few times in the last 6 months. 
She always jokes about me cheating her on and it's getting so annoying.
I have never done wrong by her ever.
Anyways she didn't know what time she started work tomorrow and she was driving so I said I will message your boss off your phone for you.. so I did, and I went into the emojis to send him one at the end and there was 👉👌👅💦 used in her most used section.. but she hasn't sent that to me? I even went all the way back 2 weeks to see if she did and If i was being silly. I asked her about it and said who have u sent that to? Cause it wasn't to me and she goes yeah it was, I always send it to you when I say let's have sex .. I said not for a while you haven't .. and she said that's cause there saved...  
Anyways when we stopped driving and we got to the place, she was all over me trying to kiss me and shit and then all of a sudden she saids she needs to do a poo , which is a form of anxiety ? Cause it's what I get when I am anxious! 
Am I being stupid ? Cause it's been since Wednesday and I can't stop thinking about it 😩😩😩😩