How do you know if you sensed God's presence?

I have felt that presence. I feel very emotional and like I might need to cry 

Somehow I know its from above 

I'm left in awe 

I have had tears of joy and assigned it to "God's Presence" . . I have experienced vast awe in the midst of an emotional congregation and assigned it to "God's Presence" . . . I have sense that sense of purpose and not being alone and assigned it to "God's Presence" . . .

When I gained Clarity and Reason, and was baptized in the waves of epiphany that brought forth rational knowledge . . . I knew that none of the former feelings . . . Had anything to do with "God's Presence".

The mind is a wonderful thing, and the situations that cause a surge in chemicals to it, can feel . . .  For lack of a better word . . Religious.

That is something I still need to figure out but I am still a believer..

Well if there would be no God then probably you wouldn't be here also. This whole universe is the prove of God's presence.