I’m in a similar situation. I have came back to work but this added on extra expense of travel cost on me. And whatever I am earning is going into bills. I am honestly looking for some extra work over the weekend or something which could add on extra income.
I'm on mat leave about to return back to work in a couple weeks, energy grants were a major help, speak with your local childrens centre as they can apply for this on your behalf, there's also council tax support, i was paying about £27 per month before the tax year, assuming you're on maternity as well when you go back to work, you can still get topped up with universal credit as well as claim 85% childcare costs+free childcare You can also get healthy start vouchers too to help with groceries x I spoke with my children's centre who sent a referral to CAB, CAB helped me with everything x
I now use a community food shop and it’s a lifesaver. £4 a week and you get over £30 worth of food. I definitely google to see if there’s one near you and give them a call. As soon as I said I had a baby and in UC when they rang I was accepted instantly
Happy to advise if you want to drop me a message. I've not been in that exact situation with a baby but I have definitely been in worse without one so can share ways to save money on bills and ways to feed you both for less!