Hiya Eeun
You are now going through what most people on here have gone through prior to IVA/Bankruptcy. You will get creditors bombarding you and they will try and scare you into paying. I would advise you to read Go4Broke IVA blog, it contains some brilliant advice on how to get creditors "where you want them". When they ring, just tell them to contact your IP, if they don't listen tell them again, if they don't listen still, repeat again and hang up. You will probably get loads of letters as well, just open them and send them to your IP.
If they contact you at work, make it clear you will not talk to them at work and make sure you read the various posts relating to harassment so you can quote the relevant regulations if necessary.
It won't be a pleasant period, but keep focusing on the fact that you are approaching the light at the end of the tunnel. If it all gets too much, change your phone no (ex directory) and only give that number out to family and friends, not to any business or company.
Good luck and try to enjoy Easter, the sunshine is free.