I'd take a step back now sidse if it was me,I've had to do this before as you get yourself so caught up in trying to resolve it.
Keep up the vagifem even doing a nightly dose to get you over this flare up,then use the coconut oil to prevent any bacteria getting a grip,slap it on as many times as you want to from morning to night but not at same time as vagifem,it's excellent for thrush etc,keep it room temperature so it stays runny,it has no shelf life as it's antibacterial apparently.it solidifies if you put it in the fridge.
Try this for a day or two and take the redbush vanilla tea instead of usual tea/coffee,you shouldn't need sugar with the vanilla one,also drink plenty water,you can also take a spoon of the coconut oil so it will work from both directions,it also helps with constipation which will take away the pressure from your bladder and help reduce the inflammation.it really is trial and error wether it's I.C or inflammatory bladder or whatever name they decide to give it,you have to test things till you find a regime that works for you it took me a long long time and I was in a terrible state with it and couldn't risk any more reactions with antibiotics,my immune system was in a really bad way.you do have my sympathy it's no joke lying there focussing on that pain so keep plodding away you will get there.good luck xx