T Nation

My TSH Level Has Suddenly Spiked

My TSH level is usually around 1.20 for the last 2 years,
I even got it checked last month and it was around that,

Iv just got a blood test done now as i wasnt feeling my self, and my TSH is 3.37,

What could cause this sudden spike?
Iv been a bit stressed lately and not sleeping great,
Because work has been non stop,

Thanks

Anybody know what this could be ?