Went to the e. r. with arrythmias and said my potassium was a 5.5 and after that i tested at the docs office and it's 4.1. whats this mean?

Not much. The number: is the concentration of potassium in the water outside cells, expressed in mEq/L. Normal (meaning common for 96% of adults sampled is 3.5 and 5.5). However, usual conc. of K+ inside cells is ~150 mEq/L. All is required is for tourniquet to be left up a bit long before sample drawn &/or some RBCs ruptured during draw & K+ conc. will be ↑. 4.1 more likely valid &/or other issues possibly involved.