There is no way that anyone can tell you how you will feel, but you could try doing a pros and cons list!
The night wakings are very normal at her age, and feeding her back to sleep is probably the easiest and quickest way to do it. Stopping this will mean going through a whole load of trauma while you work out another way to do it. It will work out, you will find another way, but it might not be as easy as quick as BFing. On the other hand you can then share this with your DH, rather than it all being down to you.
I totally understand the not enjoying it. Do you ever? Even though you resent it and don't enjoy it, do you feel that the benefits it gives as a parenting tool are worth the downsides?
Can you work out a strategy to get more me-time? If she's going to start on some formula anyway, could you try leaving formula with her and DH (or someone else) for 1/2 day while you go and do something for you? Maybe try to get 1/2 a day or a day a week that's for you, away from her? Perhaps you'll find you don't want to be away, once you find you can :)
You WILL be able to have time away from her, of course. Over the next 4-6 months she's going to start dropping more and more feeds, and need to be tied to you less and less. Would you feel, looking back in 6 months, that you were glad you stuck it out, or resentful that you couldn't do what you wanted to do in that time? Only you can work this out :)
Finally, you CAN cut down and your supply will work itself out, don't worry about that. You won't just stop making milk unless she stops feeding, and even then it will take a while now as your supply will be very stable having BF for 9 months.
You are not alone in carrying on BFing despite not enjoying it, but only you can really work out whether the benefits are worth the downsides. At the same time, specific BFing problems can be improved (such as yesterday's suggestion about watching closely and unlatching) which may be enough to make it bearable for you. Have you seen Dr Sears' page about night nursing?
www.askdrsears.com/topics/sleep-problems/night-weaning-12-alternatives-all-night-nurser