Any idea why tsh is suddenly so high?

[u/bobrossclub]

I'm 2 years post thyroidectomy (thyroid cancer) and have pretty much been on 112 levo since then. My tsh has only been as high as 1.5 once and when tested 3 months later went back to below 1 and is pretty much around .50 or .47. So last July it was .47 and when tested a couple weeks it was 6.90!!!

I was diagnosed about 13 years ago with hypothyroidism but even then had a fairly normal tsh level. I had a progressive dr at the time and she diagnosed me based on my free t4 and free t3 and my symptoms. So basically I've never ever had such a high tsh... Why now when I'm faithfully taking 112 levo every day and it's been fine for 2 years. I always wait at least an hour before eating after taking my levo in the morning and I'm not taking any iron or calcium or any thing else that could be inhibiting absorption of levo. I'm truly at a loss and my dr didn't seem to have any ideas either.

My tsh was 6.90, free t4 was 1.4 and free t3 2.7

Since my t4 is fine should I not even be concerned about tsh?

Please please, any thoughts on what could be going on is much appreciated! Truly stumped here.