Paranoia could be a problem, when people describe having had reactions to various substances, it could make you analyse everything you come into contact with. People have also described improvements and worsening that they cannot explain the cause of, unfortunately.
So let’s look at the potentials here.
Could you be breathing in metal without it being extremely hazardous to others around you? I’m guessing that metal dust would be harmful to all and your job would have to make sure they’re protecting you from that, pfs or not.
Do welders ever suffer ill effects from welding? What are they? I assume there are fumes, from the metal being heated?
Are you aware of breathing paint fumes? This (and I don’t know) sounds like something that could be more likely. People breathing paint fumes will feel lightheaded or unwell, I assume. It has a proven effect on people. Are there times that you’re not using the respirator? Is the respirator serviced and checked regularly?
It sounds to me like a job that could be quite physical. How do you respond to exercise normally?
From the list there, I think checking that the respirator is working properly would be a good call. Also does the way you feel match anyone else at work?
From the internet:
“Inhaling paint fumes for an extended period can lead to sudden headaches, nausea, fatigue, dizziness and confused or clouded thinking. If you are experiencing these symptoms, you should immediately leave the area being painted. Breathing fresh air for 15 to 20 minutes should relieve most of the symptoms. If the symptoms continue, you should see a doctor.”
It sounds like paint fume problems should dissipate relatively quickly once in fresh air. When do you start to feel bad and how long does it go on for? If you paint all day, feel generally OK, and then feel bad later, I would wonder if the paint should’ve affected you earlier in the day and if it doesn’t, if the blame should be pointed at the paint/ dust / welding or not.
People who have food reactions, certainly a couple of people I know from here, are aware quite quickly if there’s a problem. I don’t think it’s the case that they eat a difficult substance but it takes all day for them to realise.
So, to summarise, I think you need to see if your symptoms match anything else first and ask the following:
Is the protective equipment doing it’s job?
Is work providing adequate equipment to protect you from all threats?
Do you have a problem with physical exercise or work?
Sorry to not be able to give a better answer - I don’t know if it’s come up before - try searching to see if anyone else has spoken about it.
Update - Kan mentions paint sensitivity here: Can problems in the androgen receptors explain all of this?
