Bill is an overweight 59 year old man who presents to the ER with right foot ankle and calf pain for the past five days. The pain has been getting progressively worse over the past 18 hours and is now at an 9/10 on the pain scale. He has a 28 pack-year smoking history and is a Type 2 diabetic. His right foot is remarkably swollen with the calf swollen to twice the normal size. No skin lesions are noted. Bloodwork revealed a positive “D-dimer” result. Diagnosis?