I don't know what to do.

We have been dating for 3 years. It's a long distance relationship. I'm in Canada he's in the US. We both work in the trades. I'm a mechanic. He's a welder. Long story short. We have been in a really rough patch the past idk 1 or 2 months. I feel like really soon it's going to end. Things aren't the same we argue so much then don't talk for days at a time. And this is with the same guy who I truly thought I would marry someday. I'm in love with this man. But I feel like it isn't going to happen. There have been multiple cases where he's asked me if I want to stay in the relationship and such. And to make it worse, I tested positive today for a home pregnancy test. I haven't told him yet. I know I have to. But I don't think we are gonna stay as a couple. Which is depressing. If this happened 5 months ago I know for a fact that we would have. But right now I'm so scared because I feel like yes he'll be involved but not with me just the baby. Advice on how I handle this?

Also I can't tell him technically until tomorrow when he gets back to his home from work. So I will tell but it will be tomorrow.