Don't worry hun--you're not being selfish at all! Good for you for bf'ing at all and for coming on here to ask for advice on your questions.
My LO is 6 months old and we've been on "vacation" with him twice (8 hour plane ride, 6 hour timezone difference... plus time at airport, traveling to/from, etc). I combi-feed so have experience both FF and BF. If you want to offer formula, you do have more to bring with you (bottles, formula, and I always have a thermos with hot water to be able to make up a bottle anytime). However, once you're used to it then it's not much of a hassle. For me, being able to give LO a bottle whenever I need to is very useful and worth and additional 'hassle' that bringing the formula might cause. However, bf'ing is also really handy because it's a pretty easy, immediate way to calm a screaming, hungry baby!
So I would make a couple of suggestions. Depending on where you're traveling, you need to keep in mind whether you'll be able to use the water there? Will you be in a hotel, or in an apartment where you'll have access to something to heat water and possibly boil/sterilize bottles? If yes, then formula could be an option. You could also consider combi-feeding. You could bf when it works for you, and give formula or expressed milk at the other times when you're out. Then I would suggest bringing a pump to use as well (it sounds like a lot but I did this on both of our vacations and it was much less of a hassle than I expected) unless you prefer to hand express. That way you wouldn't have to give up bf'ing entirely if you don't want to.
We just recently started weaning my 6-month old so I don't know exactly how many feeds your LO would have at 8 months, but my LO now is having milk (bf or bottle) 5 times a day (once when waking up, after breakfast, twice after lunch, and once before bed). But that's more because I offer than because he's asking for it. I think by 8 months he'll be down to 2 - 3 feeds (once morning and night, and maybe sometime between lunch/dinner). Also, depending on where you go you might need to bring food/snacks for your LO while you're out so that's something else to consider.
So all in all, it's up to you! You don't have to make a decision now... you can get to 6 months and see how you feel about it then. 6 months was my goal as well, and now that I've reached it I'm just taking it one month at a time. I'm not ready to stop, and you may or may not be either
If you decide to combi-feed or switch to formula, that might be a good time to start introducing bottles (if you haven't already) to help your LO get used to it.
Good luck and have fun on your holiday!