I struggle with thinking spontaneously and following instructions - how can I cope with this?

i struggle with spontaneous thinking and following verbal instructions. I can’t respond when someone asks questions, even simple ones. For example, when my friend asked the meaning of “modest,” I couldn’t respond. Even I couldn't figure out what stopped me from responding and i don't know why I couldn't recall. I drew a blank, not because of stress. I was malnourished and used to faint up until class 5. I also had a head injury and lost blood when I was around 4 years old. I think the head injury could have long-term effects on my memory or cognitive intelligence. I can’t determine whether my memory recall problems are due to malnutrition or the head injury. I struggle with spontaneous thinking, following verbal instructions, and learning online. I often act absentminded and don’t know why. I can’t write answers or solve problems during exams, even though I can easily solve them at home later. This affects my confidence negatively. Additionally, I was stunted and am only 5 feet tall so I am vertically challenged Is there a way to deal with these situations given the effect of malnutrition on my cognitive intelligence is irreversible? Lockdown seems to have exacerbated the problem