Not nit-picky at all, anon, and thank you for your honesty!
I have noticed them too, and a lot of the time it's me not being careful and sending things before properly editing them. Most of that happens when I stay up to stupid o'clock in the morning tagging (which isn't an excuse, just me reminding myself that sleep is my friend in this instance) or, as you recalled, my phone. I notice these mistakes and kick myself after the fact because, yeah, it's VERY obvious for a character like Sherlock and makes reading his threads strange.
I will definitely be making more use of the spell check and editing tools on here from now on, until I feel confident my typos are less of an issue. Again, thank you so much and I hope I can improve in the future ^^