As long as you are betting every street you will be ok in the long run, think of it like this, if that same player keeps making the mistake of calling down with a weaker pair, over time you will be making a profit, you should be focussing less on the result and more on the decisions. if you are making correct decisions the results will sort themselves out.
this type out outdraw is common in stud especially in the low limits, sometimes if you have an opponant who you knoew will call till the end, if your aces havent improoved and his board is starting to look scary you can slow down a bit. but yeah in that situation, it sounds like he got you with a pair on 7th street, so he put in 6-7 bets with the worst hand, so you played it well and you should be happy....
i think worrying about and focusing on the results is something that can influence a player to go on tilt. so yeah, focus on your decisions, get them correct time and time again, and you will notice that after a year you will have a very healthy bankroll.