Frogslegs- you've had some good advice on how to help your breastfeeding, I'd give it all a try if you feel like you want to continue breastfeeding.
We've had a lot of "It was hard, but I struggled on and it was worth it" anecdotes, so I'm going to give my own perspective which is somewhat from the other side. I suspect I will get flamed, but I think frogslegs needs to hear this.
It is your choice as to whether you breastfeed or bottle feed. If you really feel bottle feeding would help you regain some mental stability, go with your feelings. The fact of the matter is that people will make stupid comments and judge you whichever choice you make, and how you feel it's working for you is the best gauge of whether you should continue, end of. I caught flak from HCP and members of the public for breast and bottle feeding. Everyone has a bloody opinion on what you're "meant" to be doing when you have kids, you'll get used to cheerfully ignoring it with practice
I crucified myself for mix feeding, feeling selfish for needing sleep and a small amount of time to myself. I'll be honest, and I know this wont go down well on these boards, but I fecking hated breastfeeding. Some women are fine with little sleep. I'm (no exagerration) a crazed madwoman with little sleep. Some women really enjoy the sensations of breastfeeding, I don't even let DH have much access to my boobs in the...er... marital bed, so I really disliked having a baby suck milk from them.
I remember DH taking a pic of me holding DD just after she was born, thinking "fake a smile" because I felt so bad it was utterly unnatural to smile. If I'd just gotten my DH to give her a bottle whilst I got a good 6 hour chunk of sleep (as we later did anyway), things would have been a LOT better.
If I have another child I will try to breastfeed and get better advice/support than last time, but if I'm so tired I feel like I'm about to lose my mind I'll give the baby a bottle and sleep. Life is too short, babyhood even shorter to waste beating myself up for not breastfeeding.