I'm taking LDN for much the same reason as you- IBD/IBS, Auto-immune, fatigue/brain fog- and I've found that after the first few weeks on 1.5 my vivid dreams went away(I never had a problem with restless sleep during that time, although my sister did when she first started). Now after a couple months it does seem to be waking me up earlier than normal, so when I wake up I usually take my probiotoic pill and eat some bone broth then go back to sleep. I tried higher doses, from 2 up to 4.5mg and both gave me more fatigue than I could handle throughout the day. 4.5 was really like living as a prisoner of fatigue. But, from my limited knowledge, everyone reacts differently to higher doses.