work experience question

I worked at a small firm before last year. My last paycheck was at the end of Dec, 2008 that included two extra months pay (1 & 2) for 2009 year with all health insurance being paid for the 2009.When I wrote my resume, I put Feb 2009 as the ending date of the work experience at that firm. I also asked my previous employer to verify that date. Will I get trouble for my background check? I was interviewed for several jobs recently. I really worry about my faults. Please give your feedbacks. Thank you for your generous help.