Bf mom guilt

So my son just turned 5 months old. He has been EBF since birth. However we recently started giving him a bottle of bm before bed because he seems to be unsatisfied with my boobs alone. He will take 2-4oz and then finish with breastfeeding. We don’t plan on starting solids until 6 months. I feel like I’m cheating by giving him a bottle 😕 after he goes to bed I will pump just to keep my supply up. Does this sound like a bad idea? What are your thoughts??