It is your legal right to arm yourself; though I am of the opinion that it should not be, this much certainly will not change under a republican president. The problem with gun ownership is the same for all people that do not require firearms for their job (policemen, soldiers, foresters): It escalates violence, it increases the danger of armed rampages and it is a severe danger for tragedies.
Contrasting the liklihood that a firearm really saves your life to the likelihood that it escalates violence and causes people's death yields a devastating result. Moreover, most violent conflicts arise within peer groups, so if black people, particularly those in semi-ghettoised areas, arm up significantly, I expect a significant rise in black people dieing from firearms as well. There might be an uprise in far-right motivated hate crimes, but it stands to question how much this will be a constant throughout Trump's term - I'd suspect it is a very momentary thing and one that is additionally propelled by intense reportings about that. However, an additional increase in weapon bearers is a long-term plague for society.
I cannot and will not approve of your actions in that regard and I also don't think that this is rational, but of course it is your legal right to do so. If you feel threatened I would suggest taking self-defense courses though. With firearms, either you are the one escalating the level of violence yourself, or you are already in a situation where people are pointing a gun at you, which is not the best situation to be in to draw your own one.