i'm in texas too and i'm the only vegan that i know!!  

I would suggest always be prepared.  if you fall back into eating animals for convenience, make it even more convenient to eat vegan.  stock up on luna bars, keep them in your purse or backpack, keep trail mix in your car.  if you had no choice but to eat meat in the past, now you have the choice of meat or a yummy luna bar or trail mix!  yay!

what large city are you near?  i live about an hour and a half from austin, but i can stock up once a month on things that i cant get out here.  for a while, my grocery store didnt carry vegan margarine or tofu!!!  but i talked with the manager and told him that if he stocked it, i would buy it, and since then hes added lots of fake meats.  so let your local grocery know that you are vegan and that if they stock certain things (take in a specific list to give to them), you will most certainly always go there.

another thing that i did was i baked a bunch of yummy cookies and breads and snacky things for my coworkers.  i just did it for fun, but ever since then they've been super supportive of my lifestyle which was such a nice bonus!  people stopped calling me a rabbit.  yay.

I agree with what other people said about planning ahead and having a stash of "convenience food" - I also usually always eat before I go places like potlucks and parties that will have questionable offerings.

You didn't mention if you are cooking just for yourself or for others too. I live alone and I cook four or five recipes on weekends or days off -then freeze most of it. Soup, breads, muffins, and bean dishes are favorites of mine and they all freeze really well. It is nice on long days when you are tired to just pull something out of the freezer and heat it up.

Make yourself a tasty lunch the night before. I know there are threads on Bentos here. I got a 4-part Zojurushi lunch jar at a garage sale this summer and I LOVE IT. It keeps hot things hot and cold things cold and you can cram a ton of food in there. I usually have a huge lunch plus a snack for after school in there. If you have a tasty lunch you know you like, you are less likely to eat things that might tempt you that are nonvegan. Also, if you commit to packing a lunch, it forces you to plan ahead, and then you eat cheaper and healthier as well. Bonus!

Good luck!

what people have already said is good advice.

i would study the things that you keep slipping up and eating and figure out why. is it really just convenience or is there some other issue? if it is just convenience i would do a combination of what other have suggested.

1.) figure out what you are making and buying now and how you can apply a vegan diet to that same lifestyle. say you are eating a quick breakfast like a granola bar or cereal, purchasing lunch out, and making a quick dinner... start finding vegan versions of cereal and have soymilk handy (if it isn't sold where you live you can easily make your own nut milks, but soymilk is pretty standard), make meals and freeze them in individual portions for lunches, and find quick meals that fit into your schedule (there are quick recipes on this site) at night. that's all purely hypothetical, but i am sure you get what i mean.
2.) concentrate on things that are naturally vegan... lots of produce, grains, beans, etc. if you get caught up on certain recipes and replacement foods it will makes things much harder when you don't have those foods accessible. i barely purchase any kind of replacement foods, unless you count things like tempeh and sometimes almond/soymilk.
3.) lots of spices! you can do wonders with naturally vegan things and spices. focus on a certain region and make a bunch of dishes from there to vary your diet.

ETA: oops, sorry, this is hespedal. not ans.

thank you so much! This is very helpful...
to asnwer questions, I'm in Houston, actually, and I have no idea where to go. I haven't been here too long so I'm not really sure where to look.
I have a roommate, but she's pretty willing to try new things, so two people.
And yes, it was really for convenience.  I have a lot of meetings or things that run over meal time and they always end up cooking but it's like greens with ham and bacon or cabbage with sausage so the meat has already boiled into the veggies and the meat bits are so small it can't even be separated.  But I've learned alot of things from here...
I've already started stashing a bag of carrots and trail mix...working great to hold me over!

Anybody in Houston?  Where's a food store around there?

If you have an HEB or Central Market near you you'll be able to find vegan items.  At least the ones here in San Antonio too.  Central Market (an upscale HEB) will have a lot more options but they're also a little bit more expensive.  The regular HEB's carry a decent variety of fruits and vegetables, organic juices and even meat and dairy substitutes.