Hi there, firstly do not panic. I know it's easier said than done, but the visa process is not as daunting as it initially seems. Look at it as a project at work that needs to be successfully completed. And especially if you have a straightforward case (same religion, parental consent, long association, no criminal records, travel history) then you have less reason to worry. But yes, you do need loads of patience. Maybe if you could tell us a little more about your marriage, then we could help you more.
So about your interview. ND is not looking at the number of pictures/proof to consider it 'enough', but the quality of the proofs you send. If you send them over a 100 pictures of marriage but do not send them pictures of other successive occasions, then it is deemed as 'not enough' proof. The key here is to show the progression of your relationship. How the two of you are evolving and growing in the marriage which is dependent on the amount of time you spend with each other. So collect all the proof you can of your relationship. If the husband sends the wife money, be sure to include those receipts.
I would also suggest you to send these to ND as soon as possible. Because applicants over at the Pakistan thread do this all the time. If they find out that the VO thinks there's a possibility that the marriage isnt genuine, they send in as many proof as they can. And you know what, there have been instances where the interviews have been waived! So I advise you to send them all the proofs now in the hopes of getting your interview waived. Write a cover letter explaining that you are sending extra proof to assist the VO in making a positive decision on your case. But don't entirely bank on it and continue preparing for the interview!
As for the interview, prepare well for it and take as many proof as you can. If your marriage is genuine, then you have nothing to worry about. In many cases, if they are satisfied with the interview, they will ask for the passport right away, which means that the visa is almost in the bag.
Any help you need, I think this forum and thread is always available. So dont get depressed cos this is only a phase of life. This too shall pass
All the best!