@Milesy18 - Hypothyroidism is extremely common, in those with diabetes, but also those who don't. It's just pretty common.
With a TSH of 6.8 on your last test, it seems pretty likely you may be diagnosed after the next one. Do be aware though that our thyroid hormones vary during the day; they have a bit of a vague circadian rythm, so it is important to have your tests done consistently.
The ideal time to have thyroid fucntion tested is first thing inthe morning, before you have eaten or drunk anything and were you taking any medication, at least 24 hours since your last dose.. That at least gives a consistent profile. Testing TSH at random times is a bit like stepping on the scales straightout of bed or doing the same thing, having just eaten a bit meal. The numers will vary.
If you are diagnosed, you should be monitored closesly - especially as you have a new baby and your post-baby hormones may be impacting things. If you are started on medication, it will be at a modest dose, the after testing again (and sometimes again and again) your doses will be tweaked up until your numbers look about right. Some people stay on medication a long time, and some find once their thyroids have a little help, or once their general hormone picture settles, their thyroid perks up again, so keep an open mind.
One thing I will say though is that the treatment of a wonky thyroid isn't like treating a headache. Sadly, it usually takes a while before feeling better, then it's a bit at a time. It's not like taking a headache tablet and it all going away.
I don't say that to make you despondent, but to manage any expectations you may have for following your next test.
A good diet will healp you overall, by nourishing your body and brain, without taxing it with troublesome loads.
See how you get along.