My boyfriend is acting so different

I found out in Jaunary I was pregnant and me and my boyfriends had been together on and off for about 4 years now. when he found out he was a bit shocked but wanted me and a baby in his life. The first few months of my pregnancy he was fine, not as supportive as he could have been but I dont think he understood what I was going through. Then he changes and starts putting his mates first and going out, instead of being with me and supporting me. which hurt, when I confronted him about it, he would turn it on me and say I was a nag. He went away recently on a stag weekend and I knew they were going to strip clubs but he decided to pay for a private dance which when I found out, it upset me so much. I cant do normal things like I used to and I felt he had let me down.

I also had a holiday booked for the both of us which I decided to go away with my mum. thinking sometime apart might make him relise whats important. I come back and its over he dont want to be with me, he said I dont make him happy and he dont make me happy, he dont seem to care for me. he wants to be there for the baby but thts it. dosnt want to give us a try and im finding it so hard trying to accept its over as well as coping with being pregant and a single mum. I have sent him texts saying I love him and want us to try again but he hasnt called or replied. what should I do??? I am feeling so low at the moment, everything is bringing me to tears and I just keep thinking in my head he is going to meet someone else and its heartbreaking. please give me some advice.