>Does God have a plan for me?
Yes, God does have a plan for you.
God's plan for all of us is for our bodies to be healthy. This means you need to exert your body every day and you need sunlight and probably vitamin supplements. Build up your core and become stronger and more flexible. You will instantly feel less anxious.
You also need healthy food and you need to avoid the foods that God has commanded us not to eat. Eating and sleeping patterns will mostly correct on their own as you do this, just make sure you fall asleep and wake up at the same time for like a month straight.
>little ability due to anxiety.
This will be corrected once you are more physically and spiritually fit. Just remember that you need to be physically well before you can be emotionally and spiritually well.
When I was your age I was a drug addict (with a ton of anxiety) but now I've got a sweet job, an incredible church, I am healthy and it truly is amazing. So I know you can get better also.
So anon, please just put your faith in the Holy Spirit and let Him guide you as you build up His temple, your body. You will get better.
And if thou shouldst be cast into the pit, or into the hands of murderers, and the sentence of death passed upon thee; if thou be cast into the deep; if the billowing surge conspire against thee; if fierce winds become thine enemy; if the heavens gather blackness, and all the elements combine to hedge up the way; and above all, if the very jaws of hell shall gape open the mouth wide after thee, know thou, my son, that all these things shall give thee experience, and shall be for thy good. D&C 122:7
and on a secular note, get some anxiety meds