first off, it is probably unlikely that she is pregnant if it was the only tarantula at the pet store at that time, depending on its environment it could take anywhere from 10-20 weeks for your spider to create an egg sac, once she makes an egg sac you will know if she was pregnant or not :-p but if she does have an egg sac you might want to separate the eggs from the mother, just so when they do hatch you wont have a lot of babies on her and what not, i would not worry about it to much, she could just be well fed, i have a rose haired tarantula, and when i got her she was really 'thin', and i was feeding her insects twice to three times a week, (left overs may be put into a web ball so don't mistake it for an egg sac) but then i went down to Belize and i saw tarantulas taking down frogs and mice, so i started feeding mine frozen fuzzies (mice that are prepackaged and frozen, warm them up under water until they are slightly higher than room temp, do not microwave or cook or anything and then give it to ur tarantula but move it around to make it look like its alive...feeding fuzzies is really enough food to get them through one whole molt cycle)
and it turned out she swelled up to a size of a balloon after the mouse, also, she stayed swelled up like that until a month after she molted, if you feed her a mouse you might feel like you are starving her after a while, but back in the day when i was getting my tarantulas i read that after a large meal she may not eat or drank up to a year, but just in case offer water and a bug here and there.
the few strands of web is fine, that is normal and it will build up over time, and if u want just for fun u can touch her spinnerets and she'll make a web on you which will go on forever, coconut huts are great, drift woods are fine, more things to crawl under would be better, i found that if you get one of those 'logs' that are hollow in the middle and set it up right they like crawling down in them for a while,
also the wood chips shouldn't bother her but i found that if you get this dirt form a pet store made by Exo Terra, they like to dig in the dirt, such as if u have a large rock in your tank they will go to the rock and dig under it and make holes to go in and out of all day long, um i am forgetting what the dirt is called, but it is made by exo terra and it is in a form of a brick which you put it in water and it expands into a fine dirt, it will also help keep humidity up in the tank.
btw they should molt in one large piece so if all of a sudden u see her shriveled up in the corner don't worry because it could just be her molted skin, misting her once a day will help her for when she does molt
hope this helps