I'm finding this so hard

So my eldest is 16 months and my youngest was born 2 days ago. I was pretty determined throughout this pregnancy to try breastfeeding but now that it's here I'm finding it incredibly hard.
I BF my first for around a month, (which I never intended to do) due to bad advice I introduced formula and my supply decreased until eventually he was a formula fed baby. Something which deep down I guess I have always felt a little guilty about.
Cue this time round and it is a hell
Of a lot harder than I ever imagined trying to balance my time between BF my newborn and giving my eldest sufficient attention. It can take 40 plus minutes until he is satisfied and all the while I have to stop my eldest from doing things he shouldn't when he becomes bored. I feel guilty now for a whole new set of reasons. Does anyone have any advice? Plus I know my husband misses out on bonding time because he can't get involved. 
At least whatever happens at least this time I can say that I gave it my best shot and I'm just not as hardcore as some of you other mummies out there!