Thanks for using Healthcaremagic,
After going through the all available details, you are suffering from Hypothyroidism
and your RA factor is positive but it is not clear do you have arthritis
problem or not.
Bite by brown recluse( Spider) are potentially deadly hemotoxic venom. They can cause skin necrosis; an even smaller number produce severe cutaneous (skin) or systemic symptoms.
It is good that you are treated with proper cream and antibiotics.Taking flu
shot is usually tolerated easily but few can have some reaction which should subside with in 3-4 days.
Keep yourself well hydrated and take adequate water you will recover in few days.
Your immune system may be compromised as they are auto immune diseases but it should be managable.
Hope this helps.
Take care Good Luck.
Dr.Akhilesh Dubey M.D.