Set yourself small goals, I originally said six weeks until it established but then my one and only friend who bf for a longer period said it took around 12 weeks to be really easy etc. So that became my new goal. Somewhere along the line I stopped setting goals as it helped me not to focus on it and we are now 3 weeks away from 12 months bfing.
Have you thought about a wrap that you can bf in for when you need to run errands?
Also when times get tough I would recite the benefits to myself. Which also included a purely selfish reason: not having to pack bottles of formula to go out and if I got held up out I could never run out of formula because it was on tap.
Hth, but if at the end of the day you decide to mix feed or ff then that's ok. But if you want to continue exclusively bf then ignore the nay sayers and come here for your support if you don't have any irl.
I found bh to be a wealth of knowledge and support on bfing.