R.Y.
It sounds like a combination of changes making things difficult. My older one (now 5) still likes someone to stay with him until he is asleep or almost asleep. This started when he was 2 and moved to a bed. Most times it gets worse with a sick child. You might be setting a bad habit but it might be worth it in the short term until she is completely healthy and more used to to the toddler bed.
My 5 year old has several nightlights and still claims to be afraid of various insubstantial things. Even though an adult can tell his fears are of nothing real he still can't distinguish real and imaginary very well. The "magical thinking" phase lasts from about 2 or 3 to about 7. The phantom fears are a pain but the pretend play is lots of fun.