Hi Sarah
I suffer from the same and also take fish oil supplements, I dont take multivitamins but for the last month or so I have been taking a high strength digestive enzyme formula and milk thistle and whilst I wouldn't say for definate this has helped (as like many others try multiple things as the same time) I have had alot of improvement lately, and generally my overall health feels quite a bit better.
Think it's just a case of try and see with most supplements and dietary advice, I know i always feel a bit more positive when i'm eating properly or i've read about a supplement that can help, probably the placebo effect but when you look at the alternative and the medication available from docs, anything in small doses if they can help a little cant be a bad thing....Nikki