Did you drive the vehicle?
If yes was this the same leg used to press the race(accelerator)?
What is the severity of pain?
Did you tried OTC painkillers?
Any past history of DVT?
Any family history of deep venous thrombosis?
From your history there are three risk factors which i have identified
1)History of birth control pills
2) Prolong immobilisation (Long trip in car)
3)Family history of DVT
More over its unilateral calf pain, Not suggestive of muscle pull as you have activity.So it wont be a bad idea to get an doppler sonography to rule out DVT because it is a non invasive procedure.
Check this link