Broken up after 8 years.

Partner just split up with me after 8 long years. I feel so heartbroken and lost. I am struggling to eat, sleep or even think straight. I cannot focus on anything and struggle to stop myself looking at previous messages when we were okay. It was so sudden and I actually haven’t been given a reason why apart from the fact she just wanted to live back with her mother. A small part of me believes the mother has had a slight hand to play in this as we haven’t always seen eye to eye and I am worried my partner feels like she is trapped or cannot say anything to her mother. I don’t know if that is just me trying to make myself feel better but I cannot think straight right now. We had so many good times a lot more than bad and only 2 weeks ago we were talking about engagement. The reason it hasn’t happened before now is purely financial. We were also discussing children 2 weeks ago so it seems strange to me that this has happened now. I don’t know what to expect from here but I don’t have anyone else to talk or vent too.