Hypo Thyroid Issues

My endocrynologist has stressed to me how difficult it is for people with underactive thyroid to loose weight. This is a huge point of stress in my life. I lost around 30 pounds and she couldn't believe I had done it on my own because it is so difficult. I would suggest trying a diet that is low in glycemic index and check out Jillian Micheal's book "Master Your Metabolism" if you haven't already.

Your thyroid medication is supposed to make your metabolism as normal as possible so it shouldn't be harder for you to lose weight than it was before being treated for hypothyroidism (because you're hypo... Not hyper, right?).

You say uou're hypo so my guess is that it's not harder than it was before taking medication but now you're putting more effort into tracking what you eat and you probably weigh yourself more often so it may be making you more aware of the numbers on the scale.
Still, it could happen that even on medication weightloss is almost impossible (but you're saying it's worse than it was before?). I'd do what the others suggested, low fat, low added sugar diet with a focus on low glycemic index foods and tracking what your protein intake is.

When did you start taking your medication? Ask your doctor if you think you're thyroid is getting worse, you could need a higher dose. Specially if it's been more than three/six months since your last checkup. My thyroid definitely got worse after being on levothyroxine 50mcg for a year,but that's more than long enough to need a dosage change.

Best of luck!