Gut feeling or overthinking about cheating?

How to know if it is my gut feeling or intuition?

So i am 20, my boyfriend is 26.We’ve been together for about 5 months now.Is it important to say that i am diagnosed with ocd and anxiety and i am on sertraline (anti depressant).He works a lot but finds time for me and I appreciate this.When we are together he checks his phone in front of me, i know his password, i can see who is calling, he is not taking his phone to the bathroom and etc. A couple days ago i was overthinking that he doesn’t want to be with me and etc just because he hasn’t texted for a couple hours because he was at work.Last night i had a dream that he is telling me that from the beginning of our relationship he is still seeing his ex( btw we have talked about our ex’s and we both broke up with them and he told me that he would never get back+ they broke up 3,4 years ago)Since i had this dream i started checking when is he online and i saw that at 3 am he was online on telegram.Sometimes he can’t sleep and he could have just checked something idk.But now i am overthinking that he is cheating.Is it gut feeling or overthinking and should i ask him?

Also just want to add that in the beginning we started sharing locations and he never turns it off