YANBU! Honestly OP, as others have said, it matters so little in the grand scheme of things. We all make different parenting choices - I know mums who BF for 6+ months plus and were adamant that was best, yet now the children are toddlers they eat so much junk food and watch TV all day (which I personally don't do). Different choices for different families.
I BF DS1 for 4 weeks before giving up, but that included at least 1 bottle of formula a day from 2 weeks so he was almost fully on formula anyway when we stopped. I hated BF, he was a "lazy" feeder so I had loads of blocked, painful ducts as he wasn't draining my boobs, and he wasn't sleeping at all. I was so much happier as soon as we switched and he's always slept amazingly and been so content and happy on formula up until we switched to cows milk at 12 months. He didn't even catch his first cold until he was 9 months and is rarely ill now at 3.
I'm currently combi feeding DS2 (3 weeks 5 days), with one bottle of formula introduced for the middle of the night feed after 2 weeks and now a bedtime bottle of formula as well
that we introduced a few days ago. He sleeps so well after his 2 bottles, between 3-5.5 hours at not even 4 weeks old! He's a lovely little thing but nowhere near as content as DS1 was when on bottles as he only wants to be held by me and wants to be on the boob all day if we're in the house! I'm enjoying BF much more this time round but I couldn't have coped without the night time bottles as I find the several hours cluster feeding every evening quite stressful as it is, but at least I know before bed he'll have a bottle of formula that will fill him up.
I don't think I'll stick with combi feeding long term and I imagine he will be fully on formula in a few weeks, but I want to keep going as long as I'm happy doing it. BF is definitely more convenient when you're out, although ready made formula is just as easy (but expensive!) but I actually think at home formula is easier if you have all the gear ie steriliser, perfect prep, as it takes much less time and you know how much the baby has had.
That's what's most important -
YOUR happiness. BF is better than formula in terms of nutrition only. In a few years your child will be eating things off the floor and stuffing their face with chocolate at parties just like all the others, and it won't matter how they were fed for the first 12 months of life!