DO NOT DELAY!!! GO TO A DR IMMEDIATELY!!!
Find a doctor that knows about brown recluse bites and see him right away.
You can easily lose a limb or your life.
As one who has been bitten 8 times by this type of spider (nest in my garage rafters) I can attest to all your symptoms: pain, swelling, nausea etc. Thank God my bites were one at a time and not all at once. And no, you do not feel it when they bite.
If you even think you might try to wait it out at home, just do a Google search of brown recluse bites and that should be enough to have you beating down the doctor's door. Good luck to