AMT HCl has a freebase conversion ratio of 0.874, meaning AMT freebase is about ~15% stronger by weight.
It's said to be a long one, having residual effects lasting 24 hours probably isn't unheard of. The peak effects should be almost over by 12 - 14 hours though, depending on personal physiology.
Either way, you'll be fine. People have survived much larger doses; and AMT is known for being intense. Depending on how much you need to "bail out", benzos or an antiserotonergic like Seroquel will probably help bring you down. It is ill-advised to do so this early on in a trip though - a better option is to "buy the ticket, take the ride" and just try to go with the flow and make the best of it. Put some music on and wiggle around, maybe. Have a snack. Maybe go have a shower?
In future you may want to research doses more carefully so you don't take such a hefty dose your first time

Enjoy your trip as much as you can, that's my opinion. There's no sense in fighting it.