Sometimes, more times than none, i feel slightly dizzy after eating things like bread. it's usually immediate and does not last for long, why is this?

See your PCP: Rule out pregnancy, if applicable, and seek MD attention esp if chronic, but seek urgent care if "red flags" e.g. bleeding, nausea/vomiting, fever/chills, and increased abdominal pain. Chronically, there could be underlying treatable problems such as gluten allergy, IBS, gallbladder disease,etc. Happy to consult but would require more info on past history, medications, and more details of symptom