That's exactly how it is in my country. Depending too much on oil and now that oil price has plummeted, things ain't going too well. Diversity is the key to a more resilient and strong economy. It's like having various sources of income, so when one source isn't delivering as it should, the others can help keep you going.
We have similar problem in Croatia (lack of diversification) as we rely too much on tourism, and now with Covid19, that's one of the things that was most affected.
Tourism generates approximately 20% of our BDP, and this year's revenue from tourism will go down more than 50%, so it's pretty much obvious that we are screwed, and not just this year, as I have feeling this situation might be continue in the next year as well. We are not alone in this though, all Mediterranean countries have similar issues.