I was goofing around and took a bunch of t3's. How much can a person take before overdosing?

Be careful. People almost never get seriously sick from taking a few extra T3 (liothyronine) (thyroid) tablets; this is actually fairly common. The only approach to weight loss that actually works is a combination of (1) realizing the food industry is playing you, and (2) finding some kind of aerobic activity that you actually enjoy & can share with friends / partner. Good luck.