Hi, Understand the dilemma. Hope the nose thingy heals up soon - not pleasant!
I find I can usually beat a mild case of thrush by being really careful to eat a super low-GI diet for a few days. Eating a tub cultured biodynamic yoghurt really is good (but it might take a few days for the benefits to be felt). Also garlic and garlic capsules can be good (but I'm not sure about appropriate dosage in pregnancy - I remember taking quite a lot to deal with intestinal bugs when i was pg and had no problems ). The other thing you can do is use creams like canesten etc externally only until the lifestyle measures get your internal balance back again, as a compromise.

Re cold sores - if that is what it is, I have had excellent results from using Blackmore's pimple gel when I've got one coming up, it seems to stop them in their tracks. Also good for other pussy skin conditions. It has tea tree oil, myrrh and echinacea in a gel that you rub in. Might be worth a try?
:-)