‘I am extremely anxious”.... I think that gives you the answer.
You can represent yourself, and write down what you want to say so you do not get lost for words but if you aren’t the panicky type, £300 for a solicitor will give you peace of mind that your mitigation will be put in a coherent form to the magistrates.
For your reading of 73, the magistrates guidelines are 17-22 months, so your solicitor will try to persuade the magistrates to go for the lower end. A word of warning though, you gave us some quite traumatic circumstances leading up to your arrest. Your solicitor may offer to put these forward to the court in mitigation but only get him to share what you are comfortable with appearing in the local newspaper. The details do not always appear, but the more ‘interesting’ the circumstances, the more likely it will appear in the paper.
£300 is a reasonable amount for a submission of mitigation in a guilty plea.
Your other options, as I said, is to write down what you want to day and just read it out. Get a couple of character references from local people, not relatives. Ask (if the magistrates do not offer) to be allowed to do a Drink Drive Rehabilitation Course that will reduce the ban by up to 25%.
The other option is to look for the duty solicitor at court on the day, he / she is free but it can be hit and miss if the duty solicitor is available to represent you as they give priority to cases where imprisonment is likely, and in your case that is not an option.