NICU to Perinatal float

Hey all, I've poked around allnurses every once and a while and find myself looking for some RN specific advice.

I came from a lovely NICU and I loved my job. Then I got the crazy idea I might want to go to grad school for FNP, women's health, or maybe PNP... so I took a position at another hospital in the perinatal float pool, where I will do labor and delivery, post partum, and the NICU (lower level than my previous one).

It's been about a month and a half... (I know, not that long) and I am really... not liking it at all. I get the feeling this just isn't my cup of tea.

I've only learned the post partum routine so far in the float pool, but wondering how long the 'new job blues' lasts typically? I was really excited to float to the NICU and get back in my zone but sounds like I will be bored compared to my last job. Doesn't help my old manager has said come back anytime, which makes it all the more tempting to do so. I don't want to bail and make my resume look bad, but if it isn't a good fit, how long would you give a job?

Thanks in advice.