Hi, so I'm just a few months ahead of you. Found out i was pregnant when my son was 15mo in January, am now about 13w pregnant and he's almost 18mo. In January i was still feeding him about 4 times per 24hr including bedtime and once overnight. We're now down to 1-2 times a day and are fully night weaned.
As others have said, definitely no worries about breastfeeding in pregnancy. Its completely different to people being advised to not harvest colostrum or pump: thats assuming they aren't already used to the nipple stimulation from feeding. My midwife and GP have said absolutely no problem to feed however long I want to.
I was really worried about nipple soreness and aversion as I heard they were common in pregnancy, but its not been too bad - it has got painful when he initially latches and I have to make sure his latch is really good, otherwise it hurts. But generally just for a couple of seconds and manageable.
I would strongly recommend priorising night weaning if you can, as it really really helps if you can get some better sleep. I was terrified of this as for months he'd been refusing to settle for Dad but he took it WAY better than I expected. For about 2 weeks, i purposely fed him for less time each night, until I would only feed him a for a couple of minutes each side and then rocked him. He often protested for a minute but then calmed down and let me rock to sleep. Then next step, I just removed myself from nights completely. I still fed at bedtime but husbnd responded to all wakes. First night he complained (baby not hubby!) and then second night was fine with it. Third night he slept 7.30-5.30 for the first time ever! It hasn't been totally smooth sailing, he's been teething so has had some nights with multiple wakes but only once (in about 6 weeks now) have I had to step in. I'd say night weaning has improved his sleep and its made a world of difference to me! I literally sleep in the spare room and put earplugs and whitw noise on and often now I have a full nights sleep which is incredibly helpful when dealing with first trimester woes!
We've recently managed to drop the bedtime feed, he will now have a big sippy cup of milk before bed (although we've had to push bedtime back and sometimes it is a struggle but he doesn't seem tooo bothered about no boob).
Good luck! Its absolutely do able to feed, also doable to wean. I was hoping we'd have fully weaned by now but actually I'm still enjoying the couple of feeds we have left, and also I've found my hormones have been ALL over the place with some really low moods which I don't know if its pregnancy or weaning hormones! But just a heads up, the hormones can really impact some women.
Take care, its no mean feat growing a baby and feeding a baby! I've been proud of my body these last few months.