(on edit: If you haven't filled up your tanks today, do it before tomorrow morning - 1/3 of the country's refining capacity is going off-line)
Probably too late to leave at this point, sad to say. It's now a Cat 4 (!) - and predicted to meander around the coast for a week & dump over 35" (!) of rain over SE Texas. It'll probably be weeks without power / water for that area, and many homes will be totally destroyed (probably meaning months in FEMA trailers, like with Katrina).
One 'good' thing, if you will - there'll be a home building boom in that area as a result.
Oh, and lots of water-damaged cars flooding the used car markets afterward (pun intended).
Many lives will probably be lost; hopefully, most heeded the evacuation warnings, although I'm hearing a lot of Texans were saying this was 'overblown' and wouldn't be as big as it's being made out to be - so they stayed put. 'Fake News' rears its ugly head again, if you will.
It may look 'overblown' right now...but when 36+ inches of water (rain - not even counting storm surge) arrives, it's not going anywhere, fast. There are going to be a LOT of people impacted - from Houston, all the way inland to Austin (I have some friends out there; they're OK right now.)