Shortness of breath

12 weeks and 2 days- have had shortness of breath for a few weeks now but its getting worse today. I don't feel ill at all, no coughs or colds. I do covid testing for work and it's negative. I'm asthmatic but it doesn't feel asthma related, it's as if I've done a lot and am just out of breath but I'm doing barely anything! Does anyone know what causes this? I'm worried how ill be in the 3rd trimester when it's normal to be out of breath if uts this bad already!