So I've been doing BJJ For 3 months about and before I went to vacation I didn't really gas very hard and had decent ability to sub, but poor ability to pass guard and escape from mount/side control. Now after I get back, I find myself completely exhausted for some reason. I was gone for 3 weeks and ran a couple miles here and there on vacation but now when I come back even after one week I am complete bummed out. People easily get top or guard on me easily and thats the only reason why my ability to pass guard and escape from mount is getting better as all I play are those positions. Even when I get guard, its just like I am stuck there as I lack the energy to really swiftly swing my legs for an armbar or a triangle choke. Is there something I can do to prevent gassing? I have pretty ok cardio, and I always thought my muscle endurance was pretty good.