-It may be serious. For example, if you apply for a change to status to H1-B or Permanent Residency, your applicaiton might be denied.
But,volunteer work, paid or unpaid internships, and part-time jobs can count as employment – if you do not find a job within the first two months of OPT, you should look for a volunteer position and/or an internship to work while you search for a full-time, paid position.