What Causes Persistent Low Grade Fever Along With Oedema In Legs?

26 y/o F. I've had a low grade fever for about 2 months now. My normal temp would peak at about 98.3 but now I run from 99-101. I peak around 101 or higher in the late afternoons and I'm down to about 99.5 by bedtime. Fever reducers don't help. CBC normal with the exception of 1% immature granulocytes, which is more than the preferred 0, but not enough for concern. I do have a low positive ANA 1:80 but my CRP and ESR are normal and I've never had issues with joint pains or inflammation. I've had a lot of water retention lately and my hands swell to where I can't wear wedding rings. I am hypothyroid taking meds but all by labs come back perfect. Mono test negative. MRI shows only a mucosal cyst, but the doctor says I show no signs that it's an issue (no sinus troubles at all) so there's nothing to be done about it. I just want to know where to go next to find out why I'm running fever every day. Fatigued all the time also. Not pregnant and no change in medicine, no travel. I'm out of ideas and the Internet is giving me nothing. I don't have any unexplained weight loss, which seems to be a symptom of every disease involving fever, so webmd is no help.