I'm cold -even my hands- ever since switching to a plant based diet. Am I missing something?

I'm not a doctor or a nutritionist, so I can't give any sort of medical advice, but it sounds like a circulation issue. Have you talked to your doctor about it? It has also been winter and you might be right about not getting enough calories. If it continues, talk to your doctor about circulation and in the meantime, make sure you’re eating enough daily calories. When you switch to a plant-based diet, you eat a lot more volume.