I have irregular periods and after 2 cycles of clomid(50mg and 100mg) doctor told that i was not ovulating as the progesterone levels were low(0.6 and 1.6) on cd 21. should i continue trying clomid (clomiphene) ?

Try higher doses: You could try higher doses of the Clomid (clomiphene) to allow an egg to grow, but should have an ultrasound during this treatment to ensure you have grown 1 egg and not too many!

Yes: The next step would be to increase the dose. Since you are getting close to the max doses, you should consider seeing a specialist if things dont work in the next month or two.