Having PCOS and thyroid issues myself, I know it takes a bit of patience. Just get your levels monitored by your gynac because thyroid needs to be under 2.5 during pregnancy.
Don't panic at all, TSH of 5.99 is very manageable. Just book an appointment with an endocrinologist or your gynac, get the right pill, and you are good to go.
I know seeing thyroid reports can make you feel down, but don't worry. Many moms conceive with thyroid issues once it is managed with a simple pill daily.