Please explain why I lost the low here.

[ackid]

I havent played o/8 in a while and couldnt understand why my low was not good.

I have (Ad,2d,x,x)

Flop is 8s,4s,5h

Turn is 2h

river is 8h.

the other player Im in the hand with wins with a ace high flush and has a a/3 and wins the low.

If im playing 2 cards in my hand and 3 on the board would I win the low with a/2?