My cars takin a dump on me, i need help

First of all the CEL comes on last night randomly of only pulling out of the driveway and then it is followed by a blinking O/D OFF light..now this is a concern yes..but in addition my speedo just decided to stop working while i was on the highway yay! so i got these pains in my ass and what im thinking is that theres a fault in my vehicle speed sensor on the tranny b/c in previous times the O/D OFF logth would come on during highway driving. Havent pulled the codes yet. i will later today so jus' seein if ne one has any experience with this problem or a related problem