Asalamalaikom Brother/Sister,
I once had that same feeling. It lasted for months! I had slurred speech and had trouble articulating (very frightening as I major in neuroscience!) -- constantly felt dazed, fatigued, and uninspired.
Because everything turned up normal, I started to look at what I was eating..and believe it or not I found my problem. It was diet coke. I was definitely addicted--drinking about 4 cans a day, and never thought twice about it. I thought about how many I had consumed in the past month, and did some online research. Look up "diet pepsi and MS symptoms" ...it's quite alarming.
After a week's detox of only drinking water, I felt MUCH better! More awake and vibrant.
Are you having high doses of aspartame in your diet? Maybe that could be it! That and low blood sugar, are you eating enough of every food group? working out enough? sleeping enough?
Inshallah you find the problem!!
1Sister