Hypo to Hyper without medication?

[sunshinegal07]

What is a possible explanation for going from hypo to hyper like symptoms without taking any medication?

Previous results 2 years ago:
TSH 12.6 (0.55-4.78)
FT4 around 1.0 can't remember exactly (0.83-1.63)
TPO 7.8 (normal 0-9.0) Negative
Thyroglobulin AB 2.6 (0-4.0) Negative

2 weeks ago I had dull pain and swelling of my thyroid that lasted several days. I felt completely zapped, in a fog. Then jittery and high pulse after it was over.
I went to the doctor and they reran labs and ordered ultrasound.

TSH 8.35 (0.55-4.78)
FT4 1.43 (0.83-1.63) This is the highest my FT4 has even been tested, it has been as low as 0.9.
Antibodies are not back yet.

Since that "event" 2 weeks ago I have felt a few hyper symptoms, including palpitations/raised pulse. I have more energy than I have had in a LONG time (with avoiding caffeine, which I normally depend upon). I would actually be enjoying this if my heart wasn't acting this way.

Any ideas or similar experiences?

[sunshinegal07]

Blood was drawn for repeat of antibodies, just don't have results back.

Ultrasound showed heterogenous echotexture. No nodules.

[Barb135]

You should ask to have your antibody level retested; it sounds as though you may have Hashimoto's and it's possible that when they were tested 2 yrs ago, the antibodies simply hadn't ramped up yet.  Hashimoto's is often characterized by periods of hyperthyroidism in the early stages.

There does seem to be another issue, though, since your TSH is higher than normal with a high normal FT4.  

Also be aware that some symptoms, such as the heart palpitations can apply to either/both hyper and hypo...