Have you contacted a laleche league consultant? They could be very helpful & supportive and giv eyou more options & suggestions & if nothing else, comfort. They have heard it all and are not judgemental like friends and family can be sometimes.
My son refused the breast completely after a bad bout of the stomach flu in our house. First he had it & then me. So after that he associated the breast with pain & discomfort & refused it violently. So know you are not alone. You are lucky that she will breast feed in the morning. The reason you supply is gettign low is becasue pumping does not stimulate the let down reflex like breast feeding does. he body does not get the same signals so it does nto produce a much milk.
You can try mother's milk tea to stimulate more production (you will find this at a whole foods store). Also, as hard as this is, try not to stress & feel guilty about not being able to produce as much as you want to, it just restricts the flow more. I know this is much easier said than done. Again a LaLeche league counselor can be a big help here.
Do not feel guilty about supplimenting with formula. Just be glad that you can produce some breast milk as it is best for her. I had to start supplimenting about 3 weeks after he refused the breast as my production began to dwindle, until at about 11 months I stopped pumping completely. It was a very hard decision but I just could not produce enough to make the stress worth the less than an OZ I would get each time.
As long as she is getting nutrition & she is growing you are doing your job. As he got older I also supplimented with goats milk too. This is the closest to breast milk that you can get in a store and is better than regular milk and can easily be mixed with formula.
Continue to breastfeed as long as you can in the morning (perhaps it is because she is still sleepy & there is less stimulation going on around her, try always breastfeeding in a quiet dark room where there are no distractions & this might help her to take the breast more, which will increase your supply again).
Good luck & if you need to talk more I would be willing to listen even if it is just to vent to someone who understands & has been in a similar situation.