For all new mums struggling with breastfeeding, I can say that, for me, it has been worth the stress in the end. Having said that, I also also learned to recognise when it's time to give up if it's just not right for your baby. I think my breakthrough with E came at around 14 weeks, when suddenly, out of the blue, breastfeeding wasn't a battle anymore, and she had become an efficient feeder, rarely feeding for longer than 10 minutes at a time. And since then, it has finally been the enjoyable experience I was always led to believe that it would be.
Things were different, however, with A. He got so so distressed when I tried to force him to breastfeed, that in the end I felt it was fairer to him to give him a break. After all the weeks of agonising over it, the decision to stop breastfeeding him wasn't so difficult. I carried on expressing milk for him for a number of weeks, until it became just one thing too much and we made the switch to formula feeding. Again, the decision seemed to make itself naturally.
I know this advice may not be much help, but you will always make the best decision for your baby and you shouldn't beat yourself up about it. Before I had the babies I knew that breastfeeding would be difficult at the beginning, but I had absolutely no idea what a massive challenge it would be, and how emotionally fraught. I've cried so many tears over it and being told 'persevere - it will get better' really didn't make me feel better at the time! So if the experience is tearing you apart, there's no shame at all in switching to bottles. I'm definitely a believer in the idea that a happy mum makes for a happy baby (or babies!), so you have to look out for yourself.