It sucked. Because I was doing it at home and not under observation, the dose schedule was way more conservative, so I'm not sure if it ended up saving any time at all despite the long drive to the clinic and the wait afterward. And stabbing yourself—even in the leg, as in my case—is not an easy thing to do. I thought it would get easier over time, and maybe it did a little, but there was a lot of variance and even towards the end some days it took me 10 minutes to psych myself up enough to do it. (Feeling monumentally foolish, but still not able to stick it in.)
Amusingly: after I switched to the conventional therapy of being injected by a nurse at a clinic, the nurse said she could never do it to herself. And she injects on the order of 100 patients per week!
Self-injecting into a breast... I can't even imagine. I guess the life-threatening nature, and not having an alternative, are powerful forces.