A couple things you can do. 1 lighten up by 25lbs and then add 5lbs a week back to the bar, and take another run at your top weight. You can do this over and over. When you get to a point where you can't get 5x5 or it's feeling really heavy, drop back 25lbs and take another run at it. #2, throw some curls inbetween the squats (preacher, or inclne, no low back strain) This serves a couple purposes, fills the time up, so your not rushing.
It also gives you a break mentaly, so your not thinking about the squats between sets, and you'll start to look forward to your workouts again. I've been using both these tricks with kids for years, with sucsess. 5x5 is a great program, I still go back to it myself, even after 20yrs of lifting. It's one of the best programs ever written, and strong lifts is a great sight with lots opf suport for beginers, so it's not the program, don't start jumping around, give it atleast 6mths to a year. it's worked for thousands of guys just give it time.
Make sure your getting enough food, and sleep, also since your squatting 3x a week, you only have to go heavy one of those sessions a week if you want, I personaly like Day #1 -5x5 heavy, day #2- 5x5 medium (speed) day #3 -1 set of 25 reps, slowly working up to your body weight on the bar. This is a great challange, that gives you a break from all the heavy low reps. I hope there's a couple ideas here you can use to shake up your workouts. Your on the right track, if it was easy, everyone would be big and strong. Goodluck
Let me know if you have any questions about the above ideas