Hi PB. Pardon the length, hopefully a more comprehensive picture better communicates a message.
It's to my mind quite difficult at times to decide without a few trials whether it's the T4 or the T3 - or too much or too little of either or both that's causing an issue.
The trots can be a sign of a little too much hormone, but more typically in my own case T3. It's not typical from what i've seen that it would take a month for the effect to show though - although maybe starting from not taking any it takes time to build up. (?)
It's also possible that you could have some gut and broader health issues which in their own right might be causing your symptoms, and which could underly whatever hypothyroid issues you might have.
Repeating sinus infections can be a symptom of hypothyroidism - it was in fact the first after fatigue in my own case.
While it may be necessary to take antibiotics in an acute situation, they are very hard on the gut (especially long term), and risk worsening both gut and thyroid issues.
This by encouraging candida and a reduction in the bugs we need - which may further reduce ability to take up key vitamins and minerals the thyroid needs, may reduce our ability to use what hormone we have available and feed into a negative spiral where thyroid and gut problems become mutually reinforcing.
If the gut ends up dysfunctional enough it starts to leak, and can often trigger auto immune disease - which may also as well as causing more generalised effects like food sensitivities attack the thyroid and lead into Hashis and the like. Unresolved it can eventually lead to serious immune based diseases.
Eastablishing whether or not you have a replacement dose issue is probably a first step.
Depending on whose number you apply T3 is x3 to x5 more active than T4. So adding even 10 mcg of T3 is equivalent to increasing your T4 dose by 30 - 50mcg. Which is enough to tip a person into being hyper if previously fully replaced.
While a first move could be to reverse any change in medication, it sounds like the T3 is helping you and a small dose like that seems unlikely to of itself be a major problem. (even the 10mcg starting dose I first was able to get helped me enormously though) So if you are a bit overdosed you could be on the right track to try reducing the T4. Maybe even reduce the T4 some more, and replace it with T3 using the appropriate mcg conversion factor as above.
It's going to be trial and error without bloods though, and your doc sounds helpful - maybe best to work with him?
On gut function which most docs haven't a clue about - it usually takes a good holistic practitioner.
When patients present with hypo symptoms there can be a tendency to dive straight into hormone replacement - but it may be that it's better to undertake some gut and more holistic treatment in an attempt to restore a broader balance in the body before starting replacement.
If only because it gives the thyroid a chance to recover. Starting hormone can suppress it further and end up being a one way trip.
Restoration of correct gut function is it seems enough on its own in some cases to restore proper thyroid function - as a result of restoring the ability to properly absorb/take up nutrients (including the above vitamins and minerals the thyroid and thyroid function need) and process hormone. Adding some hormone may too be necessary (at least for a while) to get the gut kick started in more seriously hypothyroid situations.
If the gut is significantly dysfunctional then piling in lorry loads of hormone and supplements may well be of little assistance because we can't absorb and/or use them - the gut is ultimately the engine room.
This (along with lifestyle, toxicity, and adrenal issues and consequent deficiencies in vits and mins like B12, D, copper, selenium and the like) seems likely to be a significant factor in why some with hypothyroidism don't necessarily benefit from taking hormone - they are simply not able to use it effectively.
The 4Rs is as before a standard approach used by holistic practitioners to work on the gut. Here's a link to a description, but it's all over the web: optimumwellnessclinic.ca/Re...
Switching to a low sugar, additives and carbs diet that seeks to reduce candia and foods triggering gut irritation is normally an important part of this.
My thyroid disease was too far advanced to recover this way (4Rs still helped enormously for about six years), but it's returned my 27 year old daughter to apparent normality after it looked like she had developed hypothyroidism in her late teens. Best of all it's put her on a path where she is conscious of her body, diet and lifestyle, and is actively managing it all to maintain her health.
It might be worth considering taking a more holistic appraoch to your symptoms - whether working on your own, or with the help of a practitioner...