Do your cat a favor and get her spayed. It will definitely help stop her from feeling so nervous and jumpy. Was she feral? That could contribute to the fear, as would abandonment. If a human abused her or hit her, or even accidentally hurt her when in a standing position this could cause her reaction as well. There's even reports that show that if a cat saw a human abusing another animal, that they would react in fear to anyone who looked like the human abuser - even if they were not the same person.
Puffing out their fur and arching their backs is what cats do when they are being confronted - they want to make themselves seem bigger towards a potential foe. This is a fear based reaction but it's also a dominance reaction. If it were totally fear the cat would run away.
Your standing may make her think that you are confronting her and being dominant. She runs away, and hisses sometimes, letting you know her displeasure with the fact that you are suddenly posturing yourself in a position of dominance.
I would suggest that you start working with your cat to get her used to you in a standing position.
The following series of steps should be done painstakingly slowly and with great patience. You must be consistent and you should do this daily. Start at five minutes and expand as you go along. Daily time with your cat is time well spent. Having a vertical perch, with different levels for her to sit on, may be helpful during the entire process, with that goal that eventually she would climb it and be beside you when you stand.
Step One: Start by lying on the floor with her. Slowly get to a sitting position on the floor. The goal is to get her to the point where she sits on your lap. Your movements should be slow and gentle, and if at first she runs away, speak to her with a calm voice while you sit. Don't force her to come to you. Use treats to get her to come near to you.
Use toys as well, a paper bag, or play the "underneath" game. If that's too much and she's too timid for that, just consistently sit on the floor until she gets to the point of being able to approach you and get into your lap and/or rub all over you. If you have a multi-tiered perch, getting her to be on the same level as you are would be helpful. This might take a few weeks, but it could be quicker - but do this daily until she's accustomed to you sitting on the floor.
Step Two would be to go from lying to sitting to kneeling. This might be killer on the knees but see if you can use a pillow. It would be the same thing - patiently get her to the point of being with you. Use a calm voice, treats, play - whatever you can to get her to the point where she doesn't run away - but plays with you.
Step Three would be sitting - not in a chair - but on a footrest or something like it - again, getting your cat to slowly get used to you in this position.
As you can see, each step slowly makes you taller and bigger but non-threatening.
Step Four is the last step, and this would be standing. You can absolutely play with her while standing with the right toys, and with a multilevel perch you could encourage her to be with you at every level.
Keep in mind that patience, taking as long a time as she needs, a calming voice and not rushing or forcing her will be the key to getting her to learn that you are not a threat. Otherwise she may always live in fear.
Also, making the time to be with your cat will give you the chance of creating a great relationship between the two of you, which, in my opinion, is priceless.