Ford Ka ‘57 overheating issues

[CalStew512]

6 months ago I had an issue with my engine where it was overheating due to leaking coolant. I took it to get it repaired, and this seemed to do the job. Since this job, I have had no hot air from my vents.
Over the last couple of days, the fan was starting to come on until yesterday when driving, the temperature light came on and steam began plooming from the bonnet. Luckily was only moments from home!
I looked at the coolant level after it cooled down and noticed it had gone down. I fillied it back up, however taking it out for a 15 minute drive today the temp light came on along with the fan, no steam, however same level of coolant.

I am no mechanic, and I’m a student. I was wondering if anyone had any advice in terms of whether this is a big fix, it would be greatly appreciated!