06 Accord Needs Jump To Start
 

So for the last couple of days, almost every time I go to start my car ('06 2.4L Accord) it's needed a jump start. Without a jump, I'll only get a couple of cranks until the dash starts flickering and the car won't start. I had the battery replaced quite recently, about 4 months ago when I put in an interstate battery from Costco. I haven't had any issues until now. Additionally, what's really strange is today the car started just fine without a jump, although it sounded like it needed a few extra cranks to get going. I went by a local O'Riley today and they said the battery, alternator, and starter are all fine although I'm thinking it may be an issue with either my alternator or starter. Does anyone have any ideas? Any advice would be greatly appreciated.