Wow, that is amazingly irritating! (ignoring all the rude comments about your age and living situation here. Not worth a real comment).
I think the mini fridge idea is a great plan. I am someone who fully understands that an extra $50 bucks is hard to come by, but if you can scrounge up the cash, check this out.
It isn't as big as most mini fridges, which run closer to $70-$100, but it might hold things like cheese and grapes :)
I get the whole "his house his rules" thing, but honestly, you didn't even get a bite of what you bought. You told him up front that you needed to eat healthier because of your pregnancy, and he was flat out inconsiderate. I would be furious if someone told me to "tone down" my hormones. Like, for real. Yeah, we get hormonal and irrational, and maybe even a tad bitchy, but WTF is a comment like that supposed to do? Sheesh. Men.
Hopefully you and your dad can work something out to where he only eats *some* of your food, and then maybe even certain things (like the granola, but not the grapes). Maybe you can decide which foods are for sharing and which are designated for the pregnant lady only. Whatever you do, good luck! :)