I went back to work full time when my DD was 10 months old. It was soiner than I'd planned to go back but I was made redundant on mat leave so when I was quickly offered a new job I felt I had to accept it as I work in a beleaguered industry.
I would have LOVED to have gone back four days and had been in talks with my previous employer about doing compressed hours, but new employer said a condition of the job was that I had to do five days.
It's been two years now and we have survived! I found getting a cleaner was a godsend - by doing five days I could justify the cost and it means I get to spend the whole weekend just doing nice stuff with my family.
it is hard at times. You have to really try to space out and sort of maximise your holidays. I had a difficult time between sept and Xmas last year when I felt like my life was a never-ending treadmill because I couldn't take any holiday in that time.
I'm now pregnant again and on my return plan to ask to do a nine-day fortnight on my return, so I'd do an extra hour a day and get every other Friday off. My company also does holiday buy and sell and I'll buy as many extra days as possible.
Since going back I have felt so jealous of people (almost everyone it seems, with this thread doing little to disabuse that perception) who are able to go back part time. It just wasn't an option for me. But maybe your work would do compressed hours or sell you some extra holiday?
My main advice would be, don't waste your time on guilt! You and your child will survive. It'll be the only reality you both know and your child certainly won't have any notion of 'missing out'.
Try to make the best of the situation you have. Use the extra money you'll earn to do lovely things with your DC and treat yourself to a cleaner if possible. And find good childcare that you are totally happy with.
You are not alone! And if anyone implies you are somehow doing a disservice to your DC by not working part time they are not worth your time. If only we could all be lucky enough to work flexibly.