Yes mine have one placenta as well. Make sure they double check at your 12 week scan though, as they got it wrong at my early scan, sonographer didn't check at 12 weeks and so we got all the way to the 20 week scan thinking they were fraternal. It changes their care plan eg identicals get more scans, but fraternal are allowed to stay in longer and go full term.
My pregnancy has been OK. I had it relatively easy the first 9 weeks and morning sickness was just nausea. But I had a subchorionic bleed at 9 and 11 weeks that was quite stressful. It cleared up at 16 weeks.
I've had a long list of pregnancy side effects eg PGP, carpal tunnel, swollen legs and feet. But no one individually has been that bad.
Having regular scans has been lovely (they're every two weeks after 20 weeks), but you can't help scrutinising every measurement worrying about big heads/little legs etc. At our 30 week scan they told us the risks of twin to twin transfer syndrome had gone from 15-20% down to 2-3% so that's very reassuring.
Being pregnant with twins is a lot of admin - lots of clinic appointments, lots of scans and the hospital often relies on us to remind them why they've made certain appointments.
TAMBA has been very useful for finding out about breastfeeding twins, sleeping positions etc. So I'd recommend you looks round their website and maybe do some of their classes/webinars. You get some discounts if you join too - I think it's £2 a month.