Re: colic and comfort nursing - ahh!
That sounds like classic cluster nursing--very normal for that age! I wouldn't worry about her getting into the habit of it, because it's a normal newborn behavior that doesn't usually continue past the "fourth trimester" anyway--no intervention needed on your part.
Both my babies were on-off-on-off fussy nursers in the evenings for a while when they were very little. My DS has sort of outgrown it now and he's 10.5 weeks.
Here's a Kellymom link about cluster feeding and fussy evenings: http://www.kellymom.com/babyconcerns/fussy-evening.html
Good luck, mama! It will get better!
Catherine, tandem nursing mama to Preschooler Girl 9/08 and Toddler Boy 3/11
Breastfeeding for 4 years and counting!