Have you had your thyroid hormone levels checked and/or tested for autoimmune antibodies for Hashimoto's or Graves disease? Do you have any symptoms of a thyroid disorder? (Hypothyroidism or hyperthyroidism?)
If the entire thyroid has increased in size, it is possible you have a thyroid hormone problem that is causing it to grow, though, the size increase for the left lobe seems like it would be within the margin of error for the ultrasound (0.1cm differences could be due to differences in the person reading the ultrasound). One of the dimensions of the right lobe has actually gone down from 1.7 cm to 1.5 cm, although the other two have increased a bit, it is hard to tell if this is actual an increase in size or due to difference in measuring. But, if the entire thyroid gland is slightly increased in size, this might indicate a thyroid problem and needs to be addressed by having your hormones tested (freeT4 and freeT3). I would not worry about the size of your thyroid, it seems like a very small increase. I have no idea how they can compare blood flow from one ultrasound to the next for the entire thyroid, and I don't know what, if any, significance that has. If my heart rate is higher during one ultrasound, would that increase blood flow? I don't know.
As for the nodules - most thyroid nodules are benign. Most doctors will not recommend even doing a fine needle biopsy until they reach a certain size criteria, and that is usually at least 1 cm in diameter if they have suspicious characteristics (so they will continue to monitor the subcentimeter 4 mm hypoechoic nodule until it is larger), the other "benign appearing" nodule would not usually be biopsied until it reaches a size of 1.5 to 2 cm.
If it were me, I would not be concerned with the nodules or the size of your thyroid at this point, but I would want to make sure I didn't have a thyroid hormone problem. (As for whether the size of the thyroid is now restricting flow of the lymphatic system causing edema - I have no idea. It seems highly unlikely a small increase in size of the thyroid would have that much of an impact on the lymphatic system, but I'm not any sort of expert on this, and all people are different). The size of the thyroid and the fact you have 2 nodules does not mean you have a thyroid hormone problem, just that it is something that is possible.
As for the edema... if this the only hypothyroidism symptom you are experiencing? There are so many possible causes for edema and I wouldn't begin to try to diagnose it based on this thyroid ultrasound. Your thyroid ultrasound isn't that different from my aunt who has nodules and no thyroid hormone problems, so I wouldn't immediately assume the thyroid was the cause of edema without more information.
If you think your thyroid is causing the edema, I would suggest posting a new question and include your thyroid symptoms (not just ultrasound) like are you tired, hair falling out, dry skin, brain fog, etc. and any thyroid hormone test results you have as well. There are many people on here who are very knowledgeable on thyroid hormone imbalances but who aren't that familiar with ultrasounds and you would probably get a better response if you included any symptoms (in addition to edema) and actual hormone test results.
Hope you feel better soon!