Postpartum.. please help me.. please

I was not diagnosed with post partum depression but I really feel like so much is taking a toll on me when it shouldnt. I wanna cry when nothing’s wrong, I feel sad, I’m definitely okay when other people are awake with me and our baby but I don’t know if I should reach out to a doctor/therapist. I was writing how I was feeling out on an app and eventually stopped doing that to try to keep track of my mental health. But it’s just so hard. I had my baby girl two months ago and my fiancé hasn’t really touched me & I haven’t touched him nor kissed for at least two weeks.... and it’s just weird. I overthink and think he’s cheating. My insecurities are eating me alive right now and my self esteem is at the WORST it’s ever been. I don’t feel like myself and when will it stop. I can’t let this consume me and upset me forever