How old is your child OP? I totally understand your situation if you have a new born. I am pretty frugal and in the first few months with our first child, I was still checking everything for value for money (even though we have plenty savings) and inconvenienced myself a lot. Are you spending more than you make or are you spending more than you would prefer to?
If it is the second, give yourself some time, say until baby is 6 months or year and wean yourself off the extra expenses.
If it is first, you got a problem. Don't go to those stores and do pack lunches. Look at the Food forum and you will find plenty of easy recipes that can be made in big batches. Give yourself time on a weekend day to make big batches. Make sure you only make what you can eat. No point cooking something and then throwing away.
What do you eat for breakfast? If you like bagels, you can buy a six pack of fancy bagels at grocery store and some fancy spread and it will still be cheaper than the 3-4 bucks you spend on a bagel everyday.
Get a good coffee maker and good coffee. Cheaper than Starbucks.
Make your changes one at a time. Don't overwhelm yourself with discipline. You are bound to fail. First tackle breakfast, then dinner and so on.
Keep track of all your expenses. A simple excel sheet would do. Once you track your week 1's expenses, lets say you spend $30 a week on breakfast. Go to grocery store and buy similar breakfast items. At the end of the week transfer the left over, say $10 into another online account. Once you get the high of being able to save while you still are enjoying a good breakfast, it will get easier.
You know what to do so just implement changes in small chunks. You will get where you want. Good luck.