Found out I'm pregnant, but....

I just found out I'm pregnant almost exactly one year since I miscarried. My boyfriend that I was dating at the time of my miscarriage and I broke up about 3 weeks ago, and we aren't on good terms at all. According to my last period, I'm about 5 weeks and I have no idea how to talk to him about it. I also started seeing someone new, and I don't know how to tell him I'm pregnant with my ex's baby. I know we're going to end that because he doesnt want kids for many more years. I just dont know what to do and I dont have anyone to talk to right now to calm my nerves. Any advice or support would be greatly appreciated