I am sure it is a training, nutrition or rest issue. Rarely is it gear. You did gain, so I'm fairly sure it wasn't bunk.
Take me for example, I want to be 320lbs lean lbs by 2008. I am currently 262lbs. If I still ate every day what it took for me to get to 262lbs, I would never reach 320lbs, I would maybe gain a little more or perhaps replace some fat with muscle, but I would certainly never reach my goal. So add in more food. Why not try adding in another daily protein shake to your program with a tablespoon or two or olive oil mixed in, some skim milk and a piece of fruit?
Rest is another factor. Rarely do people get enough sleep. Bodybuilders are as big as they are not only because of the drugs, food and weights, but also rest. Try to find a way to fit in a 15-20minute nap each day or at least on training days. Cut out some tv time if you have to, the rest is more important. Also be sure to get 8 hours sleep each night. If you still feel tired this may be too little or even too much for you. I would then try upping it to 9 hours and if you are still feeling tired, get a full check up. Something everyone should do anyway, lol.
And finally training. Are you training to gain? Are you doing weighted chins and dips, deadlifts, squats, bent over barbell rows, clean and presses, bench press, etc? If not maybe it's time to start. If you look over your training and see less and less of these lifts and more and more lifts like like concentraition curl, hammerstrength row, etc, then maybe it's time to toss them out and throw back in the tried and trues.
Also don't neglect the obvious such as taking a multi every day, minerals, 1-2 gallons of pure clean water daily. Make sure your carbs are high quality from long acting ones such as oats and whole wheats and honey, syrups and fruits for fast acting (and only right before a workout or right after!). For protein eat lean cuts of beef, chicken, tuna and other types of fish, cottage cheese, etc. Eat good fats like natural pb, olive oil, etc. Don't neglect dark leafy greens either. Add some feta cheese to salads, mayo to tuna and sandwiches. Anything to add some calories. Make all shakes in milk and add an extra scoop than you normally would.
For over the counter products, I would recommend a simple whey, multi and I can't say enough about Omega's Amplify02 stack. It really does work and if you seach my posts, I only talk about products that I've tried and that have honestly worked for me.
I really don't know what else to include to give you pretty much a quick mini crash course on gaining and gaining big. If you have gained 25lbs, the gear was not bunk. Really read my post and see how much you are doing, half way doing or maybe not doing at all. But before adding in any more gear or upping dosages, please take everything I wrote to you into consideration. Good luck with building your body. And remember building a great physique takes time. I went from 144lbs at 6'4 to my current weight of 262lbs ( I am 244 in my avi though, it is outdated!) very quickly but it took YEARS for it to have that quality, grainy look to it. Rome wasn't built in a day...... anyway, you get the idea

Good luck my friend.