Hiya Steph
Personally, I would try & reintegrate her asap - better for her & you (especially in your condition).
If you can, take mum away from the piglets & give her a quick snack (or remove piglets if you can't) while mum's eating, spray all the piglet (along their backs) with deoderant (so they all smell the same). Leave them together until mum's eaten, then put mum back in.
Hopefully, she will settle to feed the piglets & your wee gilt will naturally go for the milk-bar with her siblings. If all goes well at this stage, keep a VERY close eye on them for the next hour - if they are ok together, then all should be ok. Try not to fuss about too much (I'm a fine one talking
) but be prepared to wade-in & get her out if there's any problems.
Let us know how it goes