What could cause dizziness, lightheadedness, and symptoms of low blood sugar levels?

Hi doctor,

I have been experiencing dizziness, like a lightheaded feeling, and also symptoms of low blood sugar; however, when I checked my blood sugar with a monitor, it was 63 mg/dL. I drink enough water. As this is a regular occurrence, I checked my blood pressure during dizziness which was 110/68 mmHg. I told my doctor about this, and they did a blood test to check my thyroid, which came back normal. I regularly have around 2700 calories a day, but what I do is I have my evening meal around 6:30 PM and will only eat then around 10:30 AM, and I have a very active job. I paid to see a cardiologist and told him of my symptoms, and he did an ECG and echocardiogram, which were perfectly normal. Also, I experienced dizziness while wearing a Holter monitor, but my heart was normal. Usually, I get it at dinner time while standing up. It goes after eating something.

Kindly help.