When should i worry about a recurrent bruise?

I had blood work done 3 weeks ago ( due to a random nosebleed) and a bruise started on the samr arm of the one where the blood was drawn the next day. Havent had a nose bleed since the first almost four weeks ago and all my blood counts came back normal, although the bruise has came back today in the same spot. Overall i feel healthy but im definately a hypochondriac and still believe i might have luikemia or something serious so im thinking of getting my blood counts done again