You say you are recenrly diagnosed T2, so these symptoms are probably due to some other cause other than diabetes.
Some of your symptoms are consistent with an acute infection of the kidneys, which can affect feet and legs. The back pain, the nausea the feeling of being kicked, the tenderness could all be due to an infection, and the speed at which it hit is also a clue. Diabetes complications take some while to become a nuisance, if you get a raised temp as well then contact the NHS immediately.
Check the Sitagliptin leaflet, since i remember it can have some nasty side effects.