I am feeling nauseous and dizzy and have been having trouble sleeping and digesting food properly. my energy level is really low all the time.

Lotsa possibilities: When you just have a couple symptoms, let's say trouble sleeping & low energy level, we can make an educated guess that the problem is stress/depression, But with 5 significant symptoms, the only option is to see your doctor, provide a thorough history and work through the possibilities together ranging from ulcers to blood pressure issues to bowel inflammation/irritation to thyroid problems, etc

The food conection: What and when you eat plays agreat role in how you feel a balanced diet , not eating close to bed time (past 7pm) avoiding caffeine and alcohol as well as processed foods is important. you can also try an elimination diet to look for food allergies and intolerance such as glutten sensitivity. Ginger can help with nausea, Melatonin with sleep if no better you may need labwork and GI evaluation.

Need an exam: I would like to give you some advice but the symptoms you describe can be do to many different causes. Without knowing your medical history and being able to ask you questions it's not possible to give you meaningful advice. If your symptoms continue please see your physician.