Trouble with brands, don't know what to do

I've been on and off thyroid medication for years, because I usually feel worse when on it. Tired, lethargic, brain fog, pain in my body. Currently I'm almost 7 months pregnant, so needless to say I've been on it since. It's quite stressful, I'm not being monitored at all (northern ireland health system ain't all that) and so I keep requesting myself for my bloods to be done. Here's where I need help.

On the 50mg of Accord, I felt better than I've done in a while. My TSH however was 4.7 at one point, and in pregnancy they want it lower. My GP said it was fine though, I did not. So I got 75 mg prescribed, and the brand was Teva. That's where the trouble started. So tired I can't keep my head up, breathing issues, breathless, dizzy, depressed. I even ended up in hospital. No one made the link to thyroid medication, but when I went online, I saw I wasn't the only one doing bad on Teva. My GP never really believes me, so I went back on my 50 MG of Accord to see how I would fair, and within a week at least my head was brighter, and I was no longer dizzy and could function again. Went back on Teva, and the same thing happened again. Then I remembered that years ago, when I was in such bad shape six months after having my first baby, I got taken away by ambulance because I couldn't even stand up anymore. I was on 200mg in total of Teva at the time. Needless to say, I can't say I'm a fan of any of the levothyroxine I've been on and just feel better without...

Now the trouble. I can't get 75 mg of the Accord. I'm just going back and forth with pharmacy and GP, and nothing gets resolved. I can get 25mg of Northstar, but I know that is basically Teva too.

Does anyone have advice on what to do here? I've been taking 50mg of Accord for past few days, and just started halfing tablets this morning. Is that something you can do?

Is there another brand someone would recommend that means I get the 75mg I need?

I struggle with more auto immune symptoms and endometriosis, so my body is already under a lot of strain. I just know Teva is making me feel like close to giving up. I know that sounds super dramatic, but I already deal with daily fatigue, and this is a whole new level. I need to get this sorted before the baby is born. Sorry for the long story. After a lot of going back and forth this morning, I just don't know what to do anymore and I'm so tired of not being taken seriously by any of my health care practitioners.