Sore throat, sinus pain, fatigue, low fever & feeling miserable

I seem to be stuck in a cycle of not feeling well and it never seems to completely go away. I will wake up with a sore throat, have a headache on the front of my face, feel feverish, so I will take my temp and it is just a low fever, around 99.7. I have occasionally had an earache that comes and goes, but now it seems that the main issues are a sore throat on the left side, sinus pain, low grade fever and feeling extremely fatigued. I started having this issue over a year ago and saw several doctors who just put me on antibiotics over and over that didn't help. It seemed to come around every few months but since December I have been experiencing it every month and since March it has been every day, except for maybe 6-7 days of feeling okay. I have been on antibiotics 4 times since December and it's frustrating because that doesn't help and I'm tired of feeling this way. I saw several ENT doctors last year who couldn't figure out what was wrong so I'm at a loss as to where to go from here. I just turned 40 years old and have been healthy all of my life until now. Has anyone experienced anything like this? I'm wondering if there could be something wrong with my tonsil on the left side because that side is always sore. Some days it hurts so bad to swallow and I'm just so miserable.