2020 law graduate here
First things first. Your mental health is of paramount importance. Without protecting this, you face a much bigger battle. Please go and make an appointment with student well-being (or equivalent) at your uni. They are a fantastic service. Do not suffer in silence. They will point you in the right direction.
Second year of a law degree is notoriously difficult. Please do not panic. You are paying a lot of money for your tuition. You must go to your lecturers and tell them you are struggling. It is their job to help you. Are there any academic writing support services offered through your uni library?
I know others mean well on here, but the reality is, your grades do matter when it comes to a law career. However, what is it you want to do with your degree? Do you actually want to practice law? Do you want a city job? A national firm? Or something else? This will determine the type of grades you need to set yourself. Places like the Government Legal Dept and CPS have a minimum grade of 2:2. These are still competitive schemes, but you do have options.
Also, when you finish uni, try and get some practical legal experience. I volunteered at my local law centre for one day a week. Go to legal networking events and insight days. Get on LinkedIn. There are so many barrister chambers offering insight days and virtual mini-pupillages. Try get a paralegal job or legal assistant role after you graduate. Does your uni offer any mentoring services with alumni? You may be able to link up with law graduates.
You have plenty of options. You have plenty of time to turn this around.