Manual health is messed up when i level my characters

so i have been having this problem with all my characters, When i level my characters and i use manual health my bonus health from con keeps rising. for example my level 6 rouge is showing a +12 bonus from constitution when my CON modifier is +2 and with every level up it keeps rising.

https://www.dndbeyond.com/characters/77648894

Post the url to your character sheet so someone can take a look.

The +2 CON bonus applies to each level.  Is that where you think something is going wrong?  A level 6 character with a CON of 15 should have 12 hp total added to their rolled hit dice.  The hit point on the sheet don't look at all unusual, maybe even a little below the mean.

okay cause this is the first time i just noticed that so i was trying to make sure i was not breaking something. so to be clear the hit point bonus from Con will rise every time i level up?

You get a hit-point bonus equal to your CON modifier for every level. And if you were to increase your CON to 16 (modifier +3) at the next ASI, say level 9, you would have +27 bonus to your hit points, since the CON modifier applies for every level.

Quote from SvadroSatro >>

okay cause this is the first time i just noticed that so i was trying to make sure i was not breaking something. so to be clear the hit point bonus from Con will rise every time i level up?

Yes, you get your CON bonus hit points every time you take a level.  So as a level six character as you presented, that character would have +12.  And as Naruhoodie demonstrated, if you boost your CON at somepoint through ASIs to the +3 range, it retroactively affects your HP total.  

Max Health = rolled hp + (level x current con mod)

Let's say you're level 3 and rolled 15 and have con mod +2. 

max health = 15 + (3 x 2)
max health = 15 + 6
max health = 21

Let's say you became level 4, rolled 4 for health and took a feat with con bonus or just chose con for asi, so your con mod becomes 3. 

Rolled health goes from 15 to `19.

Max health = 19 + (4 x 3)
max health = 19 + 12
max health = 31

--

For D&D Beyond you don't need to care about the math. Just add the rolled health to the total rolled in the box and the sheet takes care of the rest.