Leaky breasts during pregnancy make no difference so don't let it worry you.
Op, your midwife is right. Having formula right to hand will undermine your confidence (and your supply if you use it). Save your money! Or spend the money on your favourite chocolate to have after birth (or before birth!).
My DS didn't latch on for 24 hours after birth (emcs) and was fine once he started - bf him until he was 20 months. Dd latched on in the delivery room (vbac) - she still loves her mummy milk at 22 months!
My advice would be try to normalise it in your head - do you have any friends or family who are nursing? Or can you stop by a bfing support group? Just seeing women nursing their babies while also doing normal things like chatting or eating cake helps!
Word of warning about some bf groups: it's often women who are struggling who attend so you may find women who've just given birth in floods of tears/pain etc. This doesn't mean you'll struggle but shows support is there if you do...
Can you take a class in bfing - either NHS or private? Do you have a la leche league near you? Or Breastfeeding support network? Make sure you have helpline numbers to hand (eg Nct). Check out the feeding section on here.
Also newborns need to nurse a lot - you may be surprised how often (I was!). Anyone around you who formula fed may be surprised too as they're used to babies who can go for longer between feeds - bmilk is more digestible than formula and baby tummies are tiny, so makes sense they need to eat every hour and a half or two hours (can feel like you're doing nothing but Bfing!). So don't let anyone stress you out with comments like 'that baby is too hungry, you should top up'. Breast feeding is supply & demand, the more the baby suckles the more milk is produced. Top ups interfere with supply by replacing time spent suckling/stimulating supply with a bottle. So keeping the baby close (skin to skin ideally) and offering the breast often is the way to go...actually, a midwife once gave me great advice - 'if in doubt, boob in baby's mouth' her logic being there's almost nothing that can't be solved by a feed! Two kids later I'm inclined to agree 
Sorry for the ramble. I think bfing is great mainly as it's free and you don't need any kit (you never forget your boobs! And I speak as someone who regularly forgot nappies when first a new mum...cue explosive leaking newborn poos and nothing to change the baby into!!). There's a tonne of support if you know where to look and it gets easier over time (like everything with babies!). The first few days will be a shock, milk coming in makes you an emotional mess, growth spurts can make you think you're losing your mind (baby is hungry again?! Wtf?!) but nature is clever and your baby knows what it needs! Just keep on til the next feed and then the next and see where you find yourself (I never thought I'd bf past 6 months!).