And no -- ARAM is not "fixed". That's just another common ARAM Bronze League™ excuse for playing like trash (and losing accordingly).
If you (genuinely) want to improve in ARAM, there's a great thread (that most players will never seen) written by some ARAM Diamond League™ players (back on Ye Olde ARAM Forum): http://forums.na.leagueoflegends.com/board/showthread.php?t=4414608
Particularly Point 8 and Point 9:
8- If the other team has better range, try to stall early game by waveclearing. It's normal to take dmg from poke, however it doesnt mean you should run in and try to fight immediately. If you run in before level 6, youll only end up either dying or burning potions. Try to stall early game (pre-lvl 6) as much as possible by getting 5 pots and some sustain. Late game tanky champions are scarier than early game poke champions.
9- If they have sustain, try not to trade. Even if you trade evenly, the simple fact that their healer is pressing W will put you and your team behind. Instead of using your spells on enemy champions when they have a Sona and Alistar, use those spells on minions to push the wave. Stay in the back, waveclear when you get pushed and wait for fights to happen later on. Healers get very efficient when small fights happen but no one dies, so thats exactly what you want to avoid.