Supply change throughout day

A little background: DD is 7 months old and eats at 7:30, 11, 2:15, 5:30 and 7:30/8. She sleeps through the night and so the 7:30/8 feeding is the last one until 7:30am. She eats cereal/fruits/veggies at breakfast, lunch and dinner. She usually gets a 5oz bottle for her 11 and 2:15 feedings.

I have an oversupply in the morning. I feed DD on one side and pump the other and usually get 5oz. When I pump at 11, I'll get 4-5oz. Lately, when I pump at 2:15, I'm only getting about 3oz. I'm concerned that I'm not producing enough milk later in the date. What can I do to help this? I'm technically pumping enough for her bottles, but I'm starting to notice her getting frustrated at night so I don't think she's getting enough. I do add milk to her cereal, fruits and veggies, so I think she's reaching the 25oz/day recommendation, but she'll be starting real food soon so she won't be getting that extra milk.

Is my supply just starting to dry up? Should I suppliment with frozen milk? Should I be eating lactation cookies, oatmeal, etc to help with supply? Should I add another pumping session at night? I'm not sure how to increase my night supply without increasing my morning supply. Or should I just not worry about that and pump more in the morning?