Visceral fat

So I gained a fair bit of weight over the winter due to being laid off and just over eating/eating too much junk and just being lazy if I'm honest.

Before that, I was a relatively fit guy. Running and hitting the weights atleast 3 times a week, I had a decent amount of muscle mass low fat - 5'10 165lbs. But over the course of 3 months I gained about 20lbs and it wasnt muscle or noticeable fat - except that my belly sticks out a little further than it used to but its still pretty solid.

Anyways, the past week and a half I've really adjusted my diet and so far have lost 5lbs. I've for the most part cut out sugar (except for coffee and the occasional gatorade lol) and empty carbs. I've also been eating a bit less - probably in a protein/calorie deficit (or whatever its called).

So my question is basically this:

Is the weight I'm losing mostly visceral fat or am I losing muscle mass as well while being in a deficit? I really dont want to lose the gains I've made and am planning to continue like this for another month while I get back down to a "healthier" weights.

Thanks for any advice, I've tried googling this but I couldn't get a clear answer pertaining to my unique situation - or I'm just a dunce