B/g so as not to drip feed:
I have always wanted to do a PhD, was accepted onto one straight off BA but didn't get funding, withdrew and never quite got back to it. Settled into a career I love, married, had DD1. Started discussing more DC but DH hesitant. It had taken several years to get pregnant with DD1 so when the opportunity came up at work to do a part time fully funded PhD I took it. DH might have said no more DC and if he said yes it might take years again to get pregnant and I didn't want to waste time.
Started September. DH decided yes to more DC in October. I got pregnant in November.
With a difficult, physically demanding pregnancy, toddler with (at this point un-diagnosed) health problems, house move, 4 days a week at very busy work with increasing responsibility I didn't manage to get ANY work done on the PhD that first year. I took an interruption of study while on mat leave with vague intentions of doing some reading while off -
- you can imagine that hasn't worked out!
Which brings us to today. DD2 is 7.5 months and I am phasing back to work 1 day a week, going back properly from April. Due to childcare costs and changes to DH job while I have been on mat leave we cannot afford for me to do 4 days, but we cannot afford for me to do 3 days either, so I am condensing my hours and doing 10 hour days. Several exciting but demanding projects have started at work and my line manager has put in paperwork to make my role full time (the increased pay would help with childcare in this case). I already feel like I can't cope - can't stay on top of the house, can't take care of myself (overweight and unfit), don't make enough time for DDs and DH, feel guilty all the time etc. Usual working mum juggling everything guilt. Oh and I have anxiety with depressive episodes and struggle a lot with mental health.
It would be absolutely crazy to start doing my PhD again from April, wouldn't it? I feel like a failure for considering withdrawing, it is something I have always wanted to do, but how will I cope? How can I give it the time and mental energy it will need? I feel like there are lots of mums who juggle study with all their other commitments and I am somehow being weak or letting the side down 
Either talk sense into me or tell me to get on with it!