Losing milk supply ?

Breast feeding moms is it normal for your milk supply to slow down a little bit? I’m still able to feed her and pump around 4-6 oz at a time when I do pump but it’s less than a few days ago. Also I couldn’t go two hours with out needing to pump because my boobs hurt so bad and now they never feel full like that, Should I start eating oatmeal or some lactation cookie? I’m just worried about losing my supply 😳