Hi, I Need Some Advice, I Have Venous Insufficiency (suffer

Hi, I need some advice, I have venous insufficiency (suffer from ankle swelling etc) since having my son 10 months ago. However over the weekend, I had to take a road trip (6 hours round trip) and woke up yesterday morning with severe pain in my left calf. I tried to elevate my leg and take it easy, but woke up this morning to the same pain. I decided to go see my Vascular Surgeon to rule out a Blood Clot. They did the Doppler exam and it came back negative for a blood clot. However, I can barely walk and my doctor actually said he didn't know how he could help me. Im really bothered and I know this pain is not normal any advice on next steps. Im wondering if the Doppler could have missed a blod clot or could it be something else?