My car is using a lot of oil and been advised to use an oil additive,being scrapped in Jan but need it for now?

I am only using it for necessary journeys to and from work and it will be scrapped under the scrappage scheme in January when a new car will be coming, hoping it would have been earlier but no such luck. I am worried sick about it breaking down before then and keep a regular eye on the oil each week. Someone suggested I use comma oil additive but don't want to make matters worse, altho they probably couldn't as i need transport because I live in a rural area with rare buses.