Cimzia (certolizumab) and weight gain

Hi, I've been on Cimzia for probably about a year now after having been on Enbrel and Humira. 

I haven't had a second to myself really in the past year between COVID and changing jobs and some other worries and I didn't even noticed that I'd gained more than 1.5 stone! Strangely the start of the weight gain coincides with my start on Cimzia...

Does anyone know if it could be related? My rheumo isn't worried about it, for him it's just from stress and nothing serious... But for me it IS serious because, not to mention the anxiety it's causing me, it's another 1.5 stone on my joints that's causing repeated sciatica...

I'm trying to see another rheumatologist soon but I don't know if they'll be just like my first rheumo and try to brush it off.

I could really use some advice, I don't know what to do anymore. I've been watching my diet, I try to walk every day, I stretch... and I'm not losing an ounce! I'm in so much more pain because of it.

Has anyone else had the same problem? Would changing medicines help me lose weight?

Sorry for the novel, but I just needed to get it all off of my chest.

Thanks xx