Having headache when trying to be mindful for too long

[Hello from Russia]

Title. When i'm trying to be present for too much time I feel this unpleasant feeling in front and lateral sides of my head. Eyebrows also get heavy and that sucks. 
Moreover I noticed  when my eyes get tired or when they are sore my ability to be present drops, I think it is because I mentally connect my "presence" to clear eyesight, perhaps I need to unwire it, should I?
Usually it's pretty good from morning to midday and then closer to night as I get tired being mindful gets harder and harder and actually "painful" physically, so I often just "shut down" and go to "sleep mode"
Do you experience the same? Is it normal? Maybe I'm forcing a little bit too much

Edited July 20, 2018 by Hello from Russia

[cetus]

52 minutes ago, Hello from Russia said:

Maybe I'm forcing a little bit too much

@Hello from Russia Exactly. Just practice being present- mindful. It should be effortless. Anything other is excess.. Throw it out.

[Hello from Russia]

@cetus56 But that is what i'm trying to do basically

Edited July 21, 2018 by Hello from Russia

[cetus]

18 minutes ago, Hello from Russia said:

@cetus56 But that is what i'm trying to do basically

@Hello from Russia  Let go of yourself. Now what are you?

[Hello from Russia]

20 minutes ago, cetus56 said:

@Hello from Russia  Let go of yourself. Now what are you?

@cetus56 Well...