Off and on headache for four days; off and on numbness and tingling in the extremities; loss of balance; inability to grasp off and on - unilaterally?

Need evaluation. : Your symptoms are neurological. You are in need of a full evaluation especially because of unilateral weakness .

Immediate attention: Headaches can be common but the other associated symptoms you describe make it more serious. Any headache with associated CNS complaints needs to be investigated urgently. The extremity involvement, balance issues and grasping difficulties speak to other nerve bundle involvement. I recommend that you see a physician immediately for full evaluation and possibly some imaging studies. Feel better.