Don't worry about it. You are allowed to correct most mistakes (including travel dates) at the interview. The interviewer will go through your application section by section, just tell the interviewer about that 5-day trip when they reach the travel section.
You can mention that the dates are not exact, but try to dig up old emails or receipts to figure out the exact dates if possible. Don't waste too much time trying to find the exact dates though; a 5 day trip is negligible unless you are pushing the limits of continuous residence or physical presence.
PD: Jan 2003 (EB3 rest of world)
I-485 Approved: July 2007
I am a layman, not a lawyer. What I write here is not official or professional legal advice. In addition, my answers on this forum are specific to the scenarios discussed in each thread and should not be generalized to other situations.