check call river. I don't like the 3b pf after you said this:
I´ve been 3betting quite a bit and gave up most of the time when I got called and missed.
if you've been busted 3betting light out of blinds, it's time to tighten up a little bit. In general, I don't like the 3b with A5 at all as a huge portion of his calling range are aces and pairs, making your hand dogshit and a leak. I'd much rather see you do this with SC's then A5. 89, 910 hit more flops and have some deception value. A5 is dominated too much when it hits and is worthless when you miss most of the time. I'd only 3b this hand if opp was loose pf, passive flop and folds to many cbets