I would ring these people as they can give you advice over the phone. They are an independent advocacy service, and they do need funding from SSD, but as your sons social worker hasn't offered it, this service may be able to contact them on you behalf for funding. You really do need someone on your side to help you fight your corner, this agency sounds ideal. At the very least they will be able to signpost you on to something else if funding isn't available. Ring them tomorrow. You need to get the ball rolling with this.
Have you told your mum yet? If not, do it ASAP. I cannot stress enough how important this is. You need to have a frank talk with her about what support she can give you and have that information ready for your next meeting. Maybe your mum could cone to it as well as an advocate. You need to pull all the stops out here.
Have you got your own solicitor? Your son will have one, SSD will have one, you must have one too.
You need to get together a clear action plan of the changes you have made, bullet point it and take it into that meeting. Have you thought clearly about the changes you are going to make? Obviously this will include the safety in your home environment, how you care for your son, who else will care for your son, the activities you do together, any nursery involvement. Break it all down, have a good think and bullet point it back here for the MN jury to rip apart. Seriously, we're fluffy kittens in comparison. But this exercise will help you get your thoughts straight and formulate a clear plan of action.
I've had a look on google and there are a few mother and baby residential units that will cater for your age group and the older child. This does need funding, and you would need a referral from psychiatry, gp or social work. Its a long shot because of the funding issues, but talk it over with the advocacy service tomorrow and see if its worth trying to add it to the pot.
Back to your mum again. You say she has no room for you to move back to her. Could she move in with you? I know you don't want to ask her, but you need to, (as long as shes not an abusive parent.) You really need to see how much support she can provide to help keep her daughter and grandson together.
If at the end of this SSD still don't want ds to come back to you, is it an option for your son to live with your mother and you have supervised contact. Not ideal I know, but at least he would still be in your life which is better than nothing.
Ok, so your tasks for tomorrow:
Advocacy service. Ring them first thing and tell them everything. See what they can do for you.
Once you've put the phone down ring your mother. Tell her everything. See what she can do to help you.
Then get a piece of paper and a pen, brainstorm and make a bullet point plan that you can take to the meeting with the changes you have made and any extra help you need from them. Bring it back here and I'll rip it apart. Remember, I only accept bullet points.
See you back here tomorrow night.