Welcome to the forum. Your AAOA has already taken a hit. It wil take time but your scores will recover. Though a yr is a bit long. Are you letting one card report a balance?
Welcome to the forum
don't close any cards proceed to the garden and meet new friends who will help you get on the right track:smileywink
Tell them your story and see how fast they respond
Welcome here great folks here for support so just head to the garden thread 
great folks here for support so just head to the garden thread
Score drop won't last forever. Keep your new accounts, let one report a small balance. You should start to see some recovery in a few months. Be patient your scores will return to high numbers.
Getting a lot of cards in a short period of time is a really common practice around here called an App Spree. When you apply for a new credit card, your score gets dinged twice: once for the inquiry and once for the new account. So when you do a large spree, all these little dings can add up to a big score drop. But not to worry, it is very temporary!
Inquiries only affect your score for one year, and drop off your reports completely after 2. New accounts can take a while to heal, but depending on how thick your file is (how many tradelines are reporting), the impact of the new accounts may go away very soon.
The benefits of a Spree include that all the inquiries age together, and that you can apply for cards without the lenders seeing the new account set up from the card you applied for right before it (there is a lag in reporting new tradelines). Anyway, I think you are doing a great job with your credit if your score is over 750 and you were approved for 5 cards. Your score will be back to that point in no time if you continue to pay on time, keep your utilization down, and sit on your hands for a few months.
Inquiries only affect your score for one year, and drop off your reports completely after 2. New accounts can take a while to heal, but depending on how thick your file is (how many tradelines are reporting), the impact of the new accounts may go away very soon.
The benefits of a Spree include that all the inquiries age together, and that you can apply for cards without the lenders seeing the new account set up from the card you applied for right before it (there is a lag in reporting new tradelines). Anyway, I think you are doing a great job with your credit if your score is over 750 and you were approved for 5 cards. Your score will be back to that point in no time if you continue to pay on time, keep your utilization down, and sit on your hands for a few months.
Do you mind sharing what cards? That way we will know if there are AF's involved, etc.
If there is no issue with you paying the AF's for all five cards (if necessary), I would keep them all as well to not hurt yourself any further! All should go up from here!