NG may test $3.75 area, it is very hard to go far down like $3.6 at this time (not many traders are brave to short NG under $3.7 at this time). Yesterday NG closed at $3.874, Ugaz at $10.52, If NG down to $3.75, Ugaz will be around $9.58...it is very possible, Further down possible, but difficult at this time.
NG is heavily manipulated by MMs, MMs play the game, I'm not suggest to average down for 3*ETF, this will add more press to you if it go down more, better wait buy sign and Trend reverse to bounce, then add to ride up.
Good luck!