When you have a blood clot your leg will usually swell up and you might get cramps like you would a normal leg cramp but sometimes the pain can be worse.
The swelling could be in only one leg or even in one arm when you have a blood clot in the leg.
If you think you might have a blood clot you should get to a doctor or even the emergency room as soon as possible since having a blood clot can be deadly if not treated soon enough.