You will definitely know when you're feeling fatigued. You will not feel rested even if you have had 12hrs of sleep, just taking a shower can wipe you out, your symptoms may feel worse (my balance and dexterity gets worse), you drop things constantly,you may have slurred speech, you feel like you're going to collapse, your body feels like your dragging lead around, you feel like you have a virus and in severe cases you can hallucinate (I suffer from parasomnia when fatigued) and all you want to do is sleep. I took Amantadine for fatigue but it did very little, however everyone reacts differently so if you're suffering it may be worth a try. Pacing yourself and good management can help. For example; don't clean your whole house, just a couple of rooms. Rest, and then do a bit more the next day. When I had a good day I would cram everything in but it would then take me 3 days of sleep to recover, so small steps only. Also, listen to your body.