flare up after booster?

I had my Spring booster on Friday (it was pfizer and I had pfizer for my 3 previous ones). I have recently been diagnosed with RA and have been on 15mg MTX for about 7 weeks. Since the booster, I have been struggling with mild fatigue and my knees are grumbling at me. Thinking that it is potentially more than just a side effect so wondering if the vaccine has triggered a flare up. I've got a telephone appointment booked with the consultant on Tuesday (however this had been booked in since about February!). Just wondering if anyone else has experienced similar?