Ok, are you hypER thyroid, of hypO? Your post says both, but your med is for hypO. If you're only taking Lev, you probably need some T3, which means either adding Cytomel or switching to Armour.
Look at the form for your bloodtest. In addition to TSH, your doc should be testing Free T3 and Free T 4. Sometimes these are called thyroxine (free) and tri-ioodothyronine (free). A quick few checks with a ballpoint pen will get you these tests if they are not marked.
Armour is available in the UK, and one way to find someone who will prescribe it is to ask a pharmacist (chemist?) for names of doctors who do. You may have to pay for it privately, but people I know who have done that say it's worth it.
To help you evaluate your own condition, a properly medicated hypoT should have a TSH at or under 1.0 - just like a healthy person. That's the whole point of being on meds to begin with! Also, you will feel and funtion the best if your FT3 and FT4 are in the UPPER THIRD of the range.
One last thing to do is check your diet for goitrogens. These inclued soy, tea, raw crucifers (cooked is ok), turnips, rutabagas, flax, millet and peanuts.
NOTE: this advice is assuming you are hypO thyroid, not HYPER.
Cheers,
Friday