It sounds like you are taking enough. I would actually be a little bit wary of taking too many supplements IYKWIM. Did you talk to your OB about other options? I know there is an iron injection you can get which may be more effective if you aren't getting enough from the supplements.

I am also too low on iron, unortunately iron tablets make me terribly constipated So I am having to force down all the red meat etc that I'd normally be happy to avoid