Welcome to the forum Moonx,
Firstly, please be aware that T3 is not a weight loss medicine. Whilst it's true that some people do lose weight when they take T3, this is certainly not the norm. For weight loss to happen, you may need to tackle your diet alongside optimising your thyroid medication.
Secondly, simply getting your T4 and TSH 'in range' is not sufficient. Most patients need their FT4 to be near the top of the range, and their TSH near the bottom of the range to stand a chance of feeling well. If your recent test results don't show that to be the case for you, then you may benefit from an increased dose of thyroxine.
As I've said to another new member this evening, self medicating with T3 should be an absolute last resort, to be taken only after all other avenues have been explored.
It may be useful to see an endo for an opinion on your case. At least if the endo thinks you could benefit from trying T3, but you then can't get it prescribed, you will have some confidence in going down the self medication route. And you may find that your endo or GP would be willing to support you with blood tests whilst you try T3, even though the medication isn't being prescribed for you.