Do your points change or go down after being promoted?

Check out AR 600-8-19, Chapter 3.
Tables 3-7 thru 3-10 shows why your points went down.
Point values for weapon qaul and APFT scores go down from E5 board to E6 board.

However, max points allowed for awards, badges, mil and civ ed go up from E5 board to E6 board also.

Yes certain things will fall off once promoted to SGT. Congrats.

Just see the promotions clerk in your S1. There are a number of possibilities. All that matters at this point is that you have been promoted. Congrats. It will be a while before the point matters again.

Points go up and down based on the needs-of-the-army for that particular rank. You cannot effect the point levels, other than being promoted. And then the army need less if that rank, and points go back up.

You don't actually have any points right now because you're not promotable yet. But, the calculations for E4 and E5 are different.

After e5 you go off of fitreps unless it change since 2015 when I got out

Yes, it happens since you get evaluated differently. I believe the APFT portion changes where instead of 180 you get 160 points