This is probably a stupid question, because I think I already know the answer, but what the hell...

I'm currently cutting, and since the middle of December I've lost about 12 lbs, so over two months that's not that bad.

I'm really trying not to lose muscle mass, so I've been hitting the gym 3 days a week (MAX-OT split). I also play floor hockey (a HITT type workout) on Sundays and I generally walk at a low intensity (very low) on Tuesdays and Thursdays.

Now, I haven't been going up in weights too much, maybe five pounds or so here and there, but I definately haven't been going down.

My question is, if I'm lifting the same (or slightly more) and still losing weight, the weight I'm losing is mostly fat right?

not always. stronger muscles are not always from bigger muscles. there are other factors. you could lift the same amount of weight and actually be losing muscle mass. if you are eating correctly, lifting weights, and not running like a mad man you are probably keeping muscle loss to a minimum though. i would worry about it unless your diet is crap which you did not mention.

Yeah, I figured I could just be getting stronger, which isn't a big concern. I'd rather be strong than huge, for now anyway.

I do very little cardio, pretty much what I mentioned.

My recent diet has been:

Breakfast
2 Eggs
190g Low-Fat Yogurt
1 Cheese String

Snack 1
1 Cup 1% Cottage Cheese
1 Banana
1 Homemade Biscotti (used whole wheat flour and protein mix)
2 Cups black coffee

Lunch
1 Can Tuna
20ml Balsamic Vinigarette
30ml Yellow Mustard
1 Cheese String

Snack 2
1 Protein Shake
1 Apple

Dinner
~130g Chicken Breast
250g Mixed Veggies

Snack 3
Protein Shake

Other:
Workout days: 1 Scoop Dextrose + PWO Shake
If I'm starving: 15g Trail Mix

I'm usually around 2050 calories a day, with a 40/40/20 mix. Sometimes it hits 40/30/30, depending on the day.