I sprained my ankle about two weeks ago and half of my foot is begining to just now bruise down to my toes. should i see a doctor or?

That's not unusual.: I would rest, ice , compress and elevate. Compress or wear an ankle brace. I would also recommend an antiinflammatory if not contraindicated. The point of going to the doctor often is to ensure you did not have any other damage. I.e. you did not suffer a fracture which could of happened. When in doubt, better safe than sorry and see the doctor.

See your doctor: It's difficult to say exactly what is going on without a good questioning session and physical examination of the problem. There could be problems with blood supply, or damaged tendons, bones, or muscle that require treatment. To prevent it from getting worse, go ahead and see your doctor ASAP. It's always better safe than sorry. Take care.

No: The bruising itself slowly makes its way to the surface as the blood leak from the injury (contusion) reabsorbs making its way to the skin surface. Unless there is increased pain or decreased range of motion, the bruising itself is normal.

Yes.: See an orthopedic doctor, who can obtain xrays, to see if there is a fracture anywhere.

Ankle Sprain: Ankle sprains are very common injuries. There's a good chance that while playing as a child or stepping on an uneven surface as an adult you sprained your ankle--some 25,000 people do it every day.​ http://www.aofas.org/footcaremd/how-to/foot-injury/pages/how%20to%20care%20for%20a%20sprained%20ankle.aspx