Right OP, first of all I highly doubt you’d be admitted to hospital because it’s almost impossible to get people admitted these days as they are so overstretched.
Secondly, you are coming across here as very lucid, conscious and in control so I would be amazed if meeting you face to face you would look in anything like as bad a way as you’d need to be to be admitted or that you’d pose a risk to DS and they would bear the breastfeeding too.
Thirdly, you mention that you have GADS but don’t feel like you have to blame everything that you feel now on that. You’ve just come out of an abusive relationship, you have a small baby and your ex is harassing you. To be frank it would be perfectly normal for anybody to feel stressed and apprehensive in that situation and if you’re getting up, getting dressed and taking care of your baby you’re being really strong and coping. Remember that he’s gaslighting you and the way you feel at the moment is because he’s been messing with your head and you’re being made to feel that your perfectly normal response to that makes you crazy or ill - but it doesn’t.
Your best bet now is to go to the GPs and explain what is happening and about the abuse and ongoing harassment. Ask them to refer you to the local Health Visitor to come and see you, they can often be a brilliant support.
Finally: Social services, if they do get involved don’t worry (in fact in your situation it might be worth asking for their support). If they get involved they may well be able to help you deal with your horrible ex and maybe even supervise his contact in a way which means you don’t have to see or speak to him. Start keeping a diary of the harassment, if it escalates SS may be able to help deal with it.
SS would also usually advocate for you within the mental health services and make sure you were prioritised because you have a dependent.
When it comes to women who’ve left abusive relationships SS really can be quite good. Their aim is usually to keep mothers and children together if at all possible, not split them up.
You really need support and SS and the health service can help you access that and they always say that asking for help if you need it Is the sign of a competent and capable parent rather than trying to hide it and cope alone.
You’re doing amazing, lots of people wouldn’t be still standing after a few months like that. But yeah, go see the GP, tell them it’s an emergency. Then go home and enjoy your time with your lovely son. You’re doing a great job.