Hey Cam, I so sorry to hear how you are feeling...it sux. My hubby Jon has been where you are. He got AS at age 27.
With regard to getting started on the NSD this link may help:
NSD Food Guide as can getting your hands on a copy of Carol Sinclair's book The IBS Low Starch Diet (she has IBS and AS). It does take time to get it sorted - a couple of months at least.
There is no harm in taking some meds if you need them while you wait to get the diet thing sorted. Jon was on NSAIDs (anti-inflammatory pain killers) for the 1st 9 months on the diet. As he made gradual improvement on the diet we was able to wean himself off them.
Please don't worry about supplements for now as it can just confuse the issue with many esp in tablet form being starchy. I would just get the diet sorted 1st give it a couple of months then maybe introduce a few supplements. Altho I have to say in my opinion with a hubby who has been on the NSD for 7 years he doesn't seem to need supplements as his diet is very healthy...but I digress.
Get your hands on some iodine from the pharmacy so you can test food for starch. Don't get the color free iodine as it doesn't work...needs to be the amber colored stuff.
Also, please don't worry about cutting out diary and sugar as you may have heard some others mention over in the NSD forum here. At this stage I would advise just strict NO starch for a few months and wait for improvement before you go cutting out other things as it probably won't be necessary.
All the best, come over into the
NSD and diet related forum and feel free to post any diet questions you have. We will try and help out best we can.
Chin up mate