The Struggle of Trusting My Own Thoughts

Another thing I’m sick of is men gaslighting me because I’m mentally ill. I can’t tell you how many times I have heard “you are just making stuff up in your head, you struggle mentally” and honestly I don’t even trust myself anymore. I don’t trust my own thoughts or things I’m seeing/hearing. I found out one of my ex’s was cheating on me by ya know looking through his phone and SEEING it and he told me I made it up in my head and I still to this day don’t know if I really saw it or if I just made it up. My current boyfriend said something that upset me and I brought it up to him and he stated “I didn’t say that” when I swore I heard him say it and his response was “you can’t remember anything” which I’m super confused about because I heard him say it I know I did. At least I think I did. I honestly don’t know anymore..