Oh poor you, you sound really shakey & miserable. Please don't worry about it toooo much (although I'm sure you will!). You don't need to be being abused to be lonely & miserable & unconfident, although of course having a not good relationship would make everything pretty awful. My point being, it's ok to feel like this & I'm not sure anyone should jump to a conclusion about why unless you want to tell them.
Sounds like you having a crisis of confidence - this doesn't mean you are being a bad mum.
Diet - at this stage, a bad diet is much more likely to effect you than the baby, the whole pregnancy thing is designed so that the baby takes what it needs from the mums body, so a bad diet will be depleting your reserves first. Can you afford to go get some pregnancy multivitamins? That would help. And if it's all a bit overwhelming try & eat one thing better a day, & see if you like it/ can stomach it. Every bit helps.
Heat - you said you doing something about that, so unless I'm missing something, nothing to worry about, you're already on it!
Info - some people like to prepare prepare prepare to feel confident about a new, big & potentially scary thing happening. Other people feel more comfortable taking it as things happen & relying on instinct/ innate skills. It's ok to be the second type of person you know, it's just a different way of dealing with things.
BUT some things are good to have a think about before hand to do with birth & just after, as it can be stressful making decisions in the moment & people firing questions at you! Do you know enough about the kinds of things you need to know for the birth? And about feeding etc? Some people make it totally over complicated (ahem, me for example!), but ther are a few important things it's good to have an opinion on. You can always ask mumsnetters questions you know!
And finally, the most important thing I think is that you've left your friends behind & it's making you feel sad & lonely. Would you like to make some new friends in your area? Are you feeling scared about it? Or a bit unsupported? It IS scary to be very pregnant & have moved & not have other people in the same situation. Internet, local groups, cafes... Lots of places to find other mums, again, we can also suggest lots of ideas, but I guess am just asking whether that would be helpful or not?