Oh you poor thing. BC I worked for a City headhunter and my boss there came back to work when her DS was only 4 months old. At the time I didn't think much of it, other than I noticed she was constantly on the phone to the nanny, worrying about her baby, and had a nightmare if he was ever ill. Also, she had negotiated to work 4 days a week with our employer, but they got a great deal as we were getting our practice off the ground and she was certainly working as hard as the rest of us on 5 day weeks.
HR is one of those jobs that is literally never finished, so you must be really stressed trying to juggle everything. I wld like to go back to work but wld never go back to the City as the commuting wld just be too much and I'd hate that whole thing of worrying about not giving anyone 100%.
Why not give up if you can afford it? You can alwways look for another job if you hate being at home. But you probably won't - you can get a job any time (as long as you can afford to be a one salary family) but you can never get those precious moment with your baby/ies back - their funny little words, steps, and so on. I know it's a cliche, but it's true.
As for waiting for no.2 - my boss ended up leaving for good once she had no.2, and never went back, so what was the point of all that stress and compromise after no.1? I think they cld have afforded for her to be at home from the start, but she went back and in doing so seemed to really resent missing out on her DS1's daily life.
You won't regret spending time with your kid(s) - you might regret spending too much time in the office. Give it a go - what's the worst that cld happen?