What can I do when I can’t think that way I suffer with depression finding it hard see my purpose in life

Even when I don't see my purpose clearly, I take the time to pray (you could meditate if prayer isn't your thing). I don't think anyone sees some clear, obvious purpose all of the time, the way you might imagine from movies or autobiographies. We're not all curing cancer, not all of the time.
If you're struggling with depression, I would encourage you to please seek treatment or continue treatment. There is no shame in taking care of yourself that way!