Papillon

Uh my nose has a deviated septum and I get allergies. I can sometimes run breathing through my mouth but if the air is too cold or too dry, it's just too hard. I've been breathing through my nose when I walk

I have experienced the same thing. I think afternoon fatigue is common especiallyif you work hard earlier in the day (or in the evening) . I hate it though. You have to get in touch with your body and learn when to post pone running for more recovery and when not to. Generally eating well will also minimise it as well as just getting fitter. . I know you're trying to lose weight but I don't believe it's right to avoid carbs if you want to do cardio/ get fit. But there are lots of different ideas about diet so you'll have to figure that out. Half a banana isn't enough.