Hair loss for reasons?

Shelly,
I have problem with my hair loss...which i could not figure out the reason why. I took Vit B5 (10g)to combat against my Acne for one month but stopped for over a month now due to substantial hair loss. Previously i suffered from hair loss due to accutane too but the hair loss has stopped although i have not quite got back all my lost hairs.
I have lost more than half of my hair now...I wonder whether the vitamins i have been taking after the VIt b5 actually cause the loss..There are Vit C-6g/day, Multivitamin from Seven seas, A chinese herbal supplements from MerryClinic in San Francisco: Website: www.merryclinic.com, Milk Thistle from NatureFarm, MSM, Lecithin, Gugulipids, Siberian Ginseng & Gingko Biloba (in one tablet from Nutralite (Amway) and I have just started on Flaxseed Oil yesterday night..as I heard it may help in fighting against acne. It sounds a lot to take all these in a day but that is what i need to fight my acne...I hope u would have some suggestions Shelly..............Thanks a lot!!!!!!!!!!!