i took wednesdays off for the first year and thought it was wonderful! it was great for me, b/c i could keep our household running better, not get too behind, and not get so invested (stressed!) about work issues. i was much more even keel.
i thought it was great for my son. he only went two days without getting a lot of mom time. This was great for us being bonded and also for keeping milk supply up (esp. since i had a hard time pumping). everyday was hard to drop off and i dont think with a baby they get what the overall schedule is- pretty much every day they go to daycare is a Monday. i did notice after vacations/extended days off, it was harder, b/c the people were less familiar, so i think having less days off in between is actually an advantage that way.
When she gets older and gets to the separation anxiety age, keeping the days together may be an advantage. i had to go back to full time a little over a year, but my mom watched him part time. at that age, he had a tougher time at daycare drop offs and the daycare people said the full time kids transition faster, which would probably apply to kids going 4 days in a row.
in an ideal world, i would start with the Weds. off and switch to Mon or Fri off as your child was ready. it sounds like your daughter may be reacting differently than mine did tho, so if her Mondays are consistently worse than the other days then i would go to long weekends.
good luck with your decision and enjoy your day off- keep it as long as you can, i miss it!!!