I generally think that when anyone decides to have a child, they should be ready and willing to go it alone if push comes to shove. Especially when you're not in a stable relationship/marriage, but even if you are. So no, I don't think it's naive for you to think about continueing the pregnancy despite his lack of support. Amazing single mothers/parents everywhere prove that it is possible to do it alone. They also prove though that it can be really fucking hard.

I'm not sure how far along you are but if you're not 100% sure, just take a couple of weeks and think things over in detail. If you can be ready for a baby, what caring for a baby and a child would look like, if you are ready to have your entire life turn on its head. How would having a child affect your long term plans, and are you and will you be okay with having some of these plans change? You might very well be connected to your ex for the rest of your life, how will you handle that? What about the financial strain? What does your support system look like?

The same goes for termination though. Sometimes people act like it's the "undo" option, but it's not. It's just one of possible actions to take after, and has consequences of it's own that a person needs to be ready for. Some women do develop a bond to the fetus early on and find an abortion very hard to handle emotionally, even traumatizing. Also, it is a more or less invasive medical procedure depending on how far the pregnancy has progressed and therefore has risks (NOT saying this to be "pro life" but people need to be real about what a termination can mean). So if that's on the table for you, you need to think about that as well.

If you think things over and find that neither raising a child nor terminating is an option for you, there's still the option of an (open) adoption.

Every choice you can make now is a major life decision. Think things over, and maybe when you're ready pull someone you trust in so you can use them as a sounding board. If you want to do it, and you have a plan of how you can do it, it's not crazy to choose to become a single mom. If you don't want to go through pregnancy or adopting out, termination is a good and valid choice. If you don't want to terminate but also don't want to get yourself into the biggest obligation of your life, for the rest of your life, adoption may be an option for you.

Wishing you all the best xx