For sure take a look at your food, but maybe consider switching up your cardio. I plateau with running real fast. I won't run for a few months, go at it for a few weeks, drop a ton of weight, and then 100% stall. Is there another form of cardio that you enjoy that's accessible? Rowing is great (on a cardio rower). Burns cals and gives you a resistance workout all in one go. Really amazing for toning. Swimming is also amazinggggggggggg for burning calories and toning at the same time.
You should also try revving your metabolism with spicy foods and caffeine. Not excessively! But, when I lived in Italy I started having a shot of espresso after lunch like everyone else and I swear it helped me digest faster and really kicked up my metab. I think it's about half as acidic and has less caffeine than a cup of coffee, so it shouldn't jack you up too much. Spicy foods also really kick up your metabolism. I am a slave to sriracha, mostly for religious reasons, but everything I've been reading lately extols the benefits of caliente).
Chin up, you'll get through this!