Another di/di here (34 weeks), but some things are similar: basically everything has higher risks, but the risks are still risks not certainties IYSWIM - the majority are absolutely fine.
Yes, you might have a tougher pregnancy (though equally, you might not - I’ve had an easier pregnancy than quite a few singletons I know). You’ll be really well monitored as you go along. I’ve had scans at least every 4 weeks since 20 weeks; for monochorionic you might get scans fortnightly; this is great because a) you don’t really have time to worry between scans and b) you get to see them loads (and figure out which one poses for cameras and which is the awkward little sod) which parents of single pregnancies mostly don’t unless something’s wrong.
If things do start to look awry at any stage, it’s probably also true you’ll get specialist attention more quickly: being officially “high risk” can be helpful in that people tend to have a low threshold for checking things out.
Other twin pregnancy bonuses: everyone is interested and nice to you; no one expects you to be anything but shattered all the time; it’s easier to make decisions about childbirth when a whole lot of options are ruled out...! (Same applies to choosing pushchairs, actually.)
Costs a fortune, mind. Join TAMBA and use their discounts, accept all help and hand-me-downs, etc... We went to both an NCT twin seminar and a TAMBA one and found them both useful in different ways: probably depends where you are.
Like all pregnancies, as you go along and pass each milestone, you’ll know where things actually are for you as opposed to the whole population. Helps to just think about what’s relevant at the moment, if you possibly can. Best of luck for a smooth pregnancy and two fabulous babies!