I bruise really easily. Doctor said I may have a low platelet level. What does this mean?

Depends on cause. Platelets help form clots. Low platelets are caused by lack of production or destruction. Immune-mediated thrombocytopenic purpura (itp), a condition where the body makes auto-antibodies against platelets, can be treated with medicines (ivig, win rho, sometimes steroids). If production is the problem, the cause needs to be found. Can be simply caused by a virus, or be as serious as leukemia.