Trade it to someone for a more practical weapon and some non radiated water. .... or... Look around.. think to myself, "well this svcks" Aim the fatman at my feet and blow myself up.

If im lucky some raider lady would stumble on me and make me her personal slave, not my preference honestly but better then dead tbh.

Lol, yeah pretty much. I love all these fancy plans some people are putting forward, but the reality is even if you have all the necessary skills to survive in such a hostile and completely alien environment the emotional trauma of realizing you just lost everything(family friends, running water, internet, etc) would do us in. It would be like ptsd times a million, we would be gibbering wrecks in need of some serious therapy.

Sell the fat man, buy a shotgun and ammo maybe armour then go hunting. Keep trading whatever I find/loot to keep myself equipped and fed till I can get the big score or more likely get killed

I would kill myself.

Mirelurks are still sea creatures right?