I can definitely tell when my meds start to wear off, because it seems like it's a lot harder to reach my thoughts, if that makes any sense. I guess that's the brain fog. But I don't typically have a major crash or a headache or anything. Now, I can also definitely tell when my meds were off because I feel more tired, but it's not usually a crash. I think it definitely is normal, but if it happens too often you might want to talk to your doctor about adjusting your dosage or something.

I start to get really agitated when my meds wear off in the afternoon and feel like my adhd is worse then I was before I started medication, only once the meds wear off...

I have only been taking Adderall for 4 days but I feel it wear off around 4 or 5pm and I feel mentally and physically exhausted afterwards. My doctor said it was normal and it is so we can relax and our brains can calm down to get ready for bed.