"I haven't had any luck since I met you?" means that I have not had any GOOD luck since I met you. As a result, I have been unsuccessful in general. The relationship between the two people could make the meaning more precise. For example, if there had been a dating relationship, it suggests that the person has not successful in love since meeting the person and maybe even after leaving the relationship.

Probably since you last met or spoke. How 's the job hunting going? I haven't had any luck.