I had a phone interview with a company on September 6th with the HR manager and at the end of the conversation she said she would get back to me the following week once she does her round of questioning with other candidates. She didn't get back to me the following week so I assumed it wasn't going to work out. however, on September 16th she sent me an email inviting me for a face to face job interview with a panel (2 others and herself). I went there the following week (Sept 23). It went very well and I sent thank you letters to everyone there. She told me she is busy this week with career fairs and she does not work on Tuesdays.
On Thursday she left me a voicemail saying that they will like to proceed with making me an offer. She would like to know my current salary, expectation, benefits that I make now so they can put the information together and present me with an offer. She told me I could send her that in an email. I did just that and sent it back telling her how excited I am about this opportunity. I received an autoreply that she will not be in the office on Friday (and once again she does not work Tuesdays). On Monday I didn't think I would hear from her since she wasn't there on Friday so I wasn't too worried. Today is Wed and I sent a follow-up email asking where she was in the process, but I have not heard back from her.
Although I'm not sure how likely it is, but I am getting concerned that they are reconsidering. How likely would that be? I know nothing is on paper and I have not stopped my job search, however, is there cause to be concerned since it's been almost a week since she left me the voicemail. I know that she took a little longer to get back to me before too, but surely if they were interested, it wouldn't take them this long?
My questions are: Is this cause for concern with the delay? How long is the process to put together a formal offer? How long does that usually take?