Sometimes the weight limit refers to total weight and sometimes it refers to per-axle.
You might have 5T (10,000 lbs) on your back axle though, in which case, that feels risky to me
Have you had it weighed on a truck scale? They'll tell you your weights on each axle. My bus -- completely gutted, so that it was just bare sheet metal and a drivers seat on the inside -- was around 16,000 lbs total. With interior fittings, batteries, water tanks, etc, I expect I am a bit under 20,000 lbs total weight these days.