If there's no chemistry between you and the prospective boss, don't take the job. Ultimately, fit is most important to success on the job. Employment agencies, headhunters, and search firms are most useful to you in covens. Never pin your hopes on just one firm or individual. The process is one of revelation of mutual needs.
First impressions overwhelm or even foreclose second impressions.
Decide what you want the other side to know or understand about you and then make sure they get that idea. Then test to make sure they got it. Do something to relieve the stress of job hunting. Regular exercise is one way to do it. A good power walk or a workout three times a week will break the spell of constant fretting about not having a job.