I'm trying to figure out if I had any business being in this hand. I won ofcourse but maybe it would have cost me.

Pokerstars NL .50/1

Seat 1: ($20.05 in chips)
Seat 2: ($58 in chips)
Seat 3: CO ($69.25 in chips)
Seat 4: BUTTON ($94 in chips)
Seat 5: SB ($86 in chips)
HERO: BB ($140 in chips)
Seat 7: UTG ($98.50 in chips)
Seat 8: UTG2 ($111.65 in chips)
VILLAIN: ($57.90 in chips)
SB: posts small blind $0.50
fashionsta: posts big blind $1
*** HOLE CARDS ***
Dealt to HERO [5d 7d]
UTG: folds
UTG2: calls $1
Villain: calls $1
1: folds
2: folds
CO: folds
BUTTON: folds
SB: folds
HERO: checks
*** FLOP *** [8d 9c 6d]
HERO: bets $3
UTG2: folds
VILLAIN: calls $3
*** TURN *** [8d 9c 6d]
HERO: bets $3
VILLAIN: raises $3 to $6
HERO: calls $3
*** RIVER *** [8d 9c 6d 7s]
HERO: bets $5
VILLAIN: folds
HERO collected $20.45 from pot
HERO: doesn't show hand
*** SUMMARY ***
Total pot $21.50 | Rake $1.05
Board [8d 9c 6d 7s 3d]

I don't get it.

You were in the BB and flopped a straight and a straight flush draw

Let's just go with "yes, it was the right play." If Villain by some miracle had [Td] and you only had 2 outs, well, that would suck. But most of the time you have plenty of outs if you're not ahead already, and you only have to call $3 on the turn. Folding that turn would be a crime.

I've decided not to listen to friend. I think I'll stick to my game.