I too have over thought my missed layups and other missed opportunities and how this not only impacted the game but what my team mates thought, then I thought about the self described "hot hand 3pt killers" in the team and how in reality they shoot at about .10% and it's not that important

Hi, brave of you to voice how you are feeling and having the insight to know what is happening.
Heaps of players experience this, which is why all professional clubs hire sports psychologists.
i encourage you to keep playing, push through and put the next foot in front of the other when you feel low and anxious. I would also encourage you to speak to your doc as experiencing anxiety on court or off court is still anxiety and a doc could get you in touch with a psych who is experienced with performance anxiety and athletes (regardless of level, the same tactics are used to work through the anxiety)
Keep playing, don't give up, it will get better.

Focus on your defense, rebounding, and making the easy "right pass". These things are relatively controllable, and they really affect winning. If you're turning the ball over a lot, simplify your passing angles, throw fewer skip passes, etc.

If you try really hard (and smart) on defense and play unselfishly and within your abilities on the other side of the ball, everything else becomes gravy.

^^ Great advice from Mick

My advice would be to focus on playing for the enjoyment of the sport and try to not take it too seriously. Easier said than done but when you screw up on the floor as much as me in recent times it becomes a necessity. :P

Read a book called "Toughness" by Jay Bilas might help

cant this person voice how they feel and ask for some tips without some jackass turning around and saying "first world problems" "perspective" really? such a troll thing to say.

my advice, as it was above - is speak to someone - this anxiety will also be apparent in work performance, relationship performance etc probably. There are some really simple things you can do and practise that will minimise and eventually eradicate the over analysing (regardless of whether positive or negative analysing is being done)

and keep playing! miss shots, turn the ball over, its all ok it happens to everyone even old Randle.

Video your games so you can have tangible evidence of failures to show how you can fix them. all your evaluation is subjective so you will tend to make them worse than they possibly are. knowing you can review your mistakes in the 3rd person should relieve you of or at least give you the tool to conquer the mental anguish you feel at that moment. you can reserve your judgement of your play until you actually see it from an objective prospective.

telling someone to lighten up, it's just a game or whatever who has anxiety makes it worse mate, not better.

experiencing anxiety is normal - it is the ability to keep it in perspective. Balance your thoughts, keep the exercise though it is a proven positive for physical and mental health.

Positive thinking and a clear mind are important.

It's all about awareness, not about worrying or thinking too much. Deep concentration and instinctive play is really important. This means not worrying about mistakes, not being negative, not worrying about the future.

Heres some interesting information from Coach Phil Jackson (Who has done more winning than anyone and at NBA level) that talks about this area:

"Basketball is a complex dance that requires shifting from one objective to another at lightning speed"

“To excel, you need to act with a clear mind and be totally focused on what everyone is doing on the floor.” ”Some athletes describe this as a cocoon of concentration”

“The secret is not thinking. That doesn’t mean being stupid, it means quieting the endless jabbering of thoughts so that your body can do instinctively what it’s been trained to do without the mind getting in the way”

Phil Jackson explains that an area he had to improve with his game and an area he has taught pro athletes was not to have a hyperactive, hypercritical mind. Instead athletes should quiet their judging mind and focus on what needs to be done at any given moment.

One way they do this is by teaching athletes meditation so they can experience stillness of the mind.

“A lot of guys second guess themselves, they don’t know whether to pass or shoot or what. But If I’m open, I’ll shoot, and if I’m not, I’ll pass. When there’s a loose ball I’ll go after it. The game happens so fast, the less thinking and the more you react to what’s going on, the better it will be for you and your team”