Feel free to use a stand mixer or hand blender, I'm showing how to do this if you don't have those. Secure your bowl in a sauce pan over a tea towel which stops it from being wobbly and you'll have a spare had for pouring in the oil. Then separate the eggs and put the yolks in the bowl.

Add vinegar and mustard to egg yolks then whisk constantly while adding the oil very VERY slowly. You can stop pouring in whenever you like but don't stop whisking,

Keep whisking until the mixture resembles mayonnaise, season and reserve in the fridge.

In the 1st image I deliberately added the oil too quickly and didn't whisk enough = split mayo. To recover add 1 egg yolk into a bowl and add 1 tsp of cold water (not sure of the science but Gordon Ramsay said so) Now add the split mixture very VERY slowly to the yolk and whisk constantly, If your split mixture is lumpy then add it a spoon at a time.

So your mayonnaise should be just fine, if it's a bit thin for your liking just add another 50ml of oil, I though I'd show you my BLT that I made using this lovely mayonnaise. https://www.youtube.com/watch?v=9IUVLVTL6HI