Heads up no limit

Yesterday I had a good day at the HUNL tables. Finally. Plus 2 buy ins. It's not that great but I'm happy since it's a nice change to finally win something after losing all the time. I play on Party with only 6 BI bankroll which is not recommended, of course, but I don't want to make a deposit. To be honest, it's not recommended to play on Party at all because of their ridiculous rake. My goal is to feel the game and see if I'm good enough to play HUNL and then I can go somewhere else and play seriously. Right now I'm table selecting like mad, I play only shortstackers and really weak players who don't raise preflop and quitting everyone who raises their first 2-3 small blinds.

Overall, I'm 1 BI down after 2250 hands. I'm losing with three of a kind, mainly because of this hand:

SB - $15
Hero (BB) - $50.85

Pre-flop: ($0.75, 2 players) Hero is BB 3 3
SB calls, Hero checks

Flop: J T 3 ($1, 2 players)
Hero checks, SB bets $1, Hero raises to $3, SB goes all-in $13.50, Hero calls $11.5

Turn: 6 ($30, 2 players)

River: K ($30, 2 players)

Final Pot: 9.5 BB
SB shows: A Q
Hero shows: 3 3

This was the only hand where I had trips and we went all-in.

Some interesting stats:
AA lost $15
AKs lost $15
JJ lost $27 (2 preflop all-ins, against Q3o and Q9o, lost both times; first against runner runner flush and second time he hit 2 Q, on flop and river)

Overall, I know I'm not playing well enough and to be honest, I'm not trying to study this game at all, just trying to feel the game since I don't have time to study poker right now. But I will, as soon as possible.