that actually is unprofessional. the proper way for a professional to resign is to give 4 weeks notice. that way if they will have time to find someone else to fill your position. you also should not use your vaca time as notice. it is unfair to the employer and they have the right to refuse to allow you to take that ime off. 
when i left my job in a hospital(i worked there 8 years) i had over 40 days of vaction. i just had them pay me for it. 
John