A few pointers:
1.) Weigh every day and total the last 7, then divide by 7. That's your true weight, allowing for water and poop fluctuations.
2.) If you use a spring scale, make sure it's in a temp controlled room. I found that they weigh you as less when they are cold, more when hot.
3.) The scale is used in conjunction with the mirror and/or calipers, observing BF. By itself, weight is not an indicator of lean mass.
4.) It IS possible that you lost fat and gained mass, but it is a rarity for any intermediate lifter. Usually, if you didn't gain weight, you didn't eat.
5.) The first week or so of bulking you feel like a bursting balloon. It takes a bit to acclimate to the extra cals.
There are a hundred threads in here about bulking. Look for posts by Tot, Lol, Bluejacket, Aaron, Dan Moore, Bulldog, our new guy Quantum or me. And many others. Bulking is one thing I can do well, heheh.
Bulking is pretty easy. Cutting is another story.
I do because I can.
I can because I do.
Squat, bench, chin, deadlift, dip, row. The rest is secondary.