I keep remembering things that might help - so here's another! When you 'top up' you are using a bottle (I assume), and the early use of an artificial teat of any kind (bottle, dummy, nipple shield) can cause nipple confusion. I started using a dummy on baby no 1 years ago (when it wasn't frowned upon!) and she then did exactly what your DS did last night...refused both breasts and completely freaked out. It is so confusing for them, as the nipple and the rubber teat feel so different. They don't know what is going on.
I got rid of the dummy, and within a day or so my dd was back to her normal feeds. Your DS will accept your breast again when he is hungry enough, but it really sounds like he was 'nipple confused'. They are usually more easily confused at night time when they are half asleep, and trying to get them to feed at that point can be so frustrating for both of you. Google this for more info.
Can I suggest you cut out the bottle completely. This is what I think will then happen, just so you know what to expect.
1/ bottle cut out - solely breastfeeding now to get rid of nipple confusion.
2/ baby needs feeding much more often as bottle was filling baby's tummy beyond what it could naturally take. Expect feeds to be every hour for a day or two until milk supply improves.
3/ baby might be frustrated for a day or so, whilst you are waiting for supply to improve, but this is no different to when baby has a growth spurt so it will prepare you for the 6 week growth spurt and the 3 month one too!
4/ after a day or two your supply will have improved...keep feeding baby on demand, not to a set time (that's for bottle fed babies) and he should be happy and your supply will be just right for his needs.
Over time, as baby's jaw gets stronger, he will feed quicker, and will take more during each feed, so the gap between feeds will grow. THAT'S when breast feeding finally pays off for YOU! No carting bottles around and trying to heat them up and no expensive milk purchases! I really hope you persevere and get to that stage. I'll stop writing now...best of luck and really well done for asking for help instead of giving up :)