Can an ulcer or gerd effect your brain as well? like lightedness, cloudy, trouble concentrating?

No: The symptoms you describe are not related to GERD or ulcer. There are more likely from a different cause, which could include medicines, anemia, depression, etc. Speak to your doctor about these symptoms and they can work on a further evaluation with you. Best wishes.

Not classically: Unless you are bleeding significantly from the ulcer or have significant pain and inability to eat. Additionally, if you are taking medications for these conditions that could cause symptoms such as you mention above, depending on the meds you are taking, if you are taking any at all. Hope that helps.

Health affects mood: There is no reason that GERD or peptic ulcer disease should have a direct effect on brain function. However, it's commonly known that when people are diagnosed with a medical condition, it often affects mood negatively. Mood disorders often result in vague body complaints like headache, dizziness, stomach upset, muscle aches, fatigue,etc. If you are worried about persistent symptoms, see a doctor.