Imminent unemployment, I have a screwed up CV; incompetent in my own field of PhD. Hoping for some perspective and advise? I did my PhD recently and it took 5.5 years to complete. I had just 2 courses in my PhD, so the timeline is excessive owing to my lack of motivation during my 2-3rd year. 

I have also not taken any advanced graduate level courses in my PhD and am entirely relying on my publications for portraying my quantitative, technical and programming experience. 

I had changed my field from materials engineering (undergrad) to mechanical engineering during PhD. But, I did not take any courses to address the lack of technical background (advanced mathematics and computational fluid dynamics).

My research was not that rigorous programming and technicality wise. So, I kind of survived through it. Studying other publications, self studying concepts through books was enough.

But now, since I have graduated, I am finding it severely uncomfortable to apply for positions that seek a different more rigorous job description.

I think, I made some terrible decisions along the way. I should have taken the courses as that would have built up my confidence. 

On top of that, I have no job experience or internship experience. I have lost hope on academia and chances in industry appears slim too. 

I have 6-7 months of a temporary gig to regroup myself and survive from imminent unemployment. Hoping for some perspective and advise?
Actually, I think that the way you did your doctorate implies that you can, in fact, learn the things you don't know now. In fact, you may have more skills than you realize, but I'll leave that aside. 

But first, the courses you took in the past are nearly irrelevant to the process of getting a job once you have a doctorate. The skills, yes, but not the courses. But few employers will feel the need to do any real examination of your coursework. 

I agree, however, that having some structure to learning is a big help. But you can address that in a variety of ways. Your alma mater might permit you to take some courses for a reasonable fee, especially if there is some service that you can supply to them in return. This might be an option if you do wind up unemployed for a bit. 

But there is now a world of online study possibilities. For many people they have little actual value, since the credential they come with might be suspect, but you don't need credentials at this point. But, if you do sign up for online instruction somewhere, be aware that just reading and watching videos isn't enough. You need to put the new information into practice so that it becomes actual knowledge. Use exercises for reinforcement and try to find a place that will also give you appropriate feedback on your work. Some online courses are better at this than others. 

So, I think that a two track plan would be worth pursuing. Work both in the job-seeking realm but also in filling in knowledge. 

If online courses don't appeal to you, but you have research skills, then there is no reason that you can't start on some project that requires the skills you don't have but can, as you did in your previous work, fill in via self study. If it results both in publications and in skill building all the better. Perhaps your old advisor can help point to some things, even if you are now remote.