Rhogam shot side effect?

I got my rhogam shot on Friday. (First pregnancy, 30 weeks).

Today I went to the mall with my fiancé, I was feeling fine & out of no where I started feeling dizzy, shortness of breath, hot flashes & a tight back ache. So we went home.

I rested, felt better & went back to the mall, & then out of no where i started feeling the same way.

I don’t know if it me getting anxiety or if I’m experiencing side effects.

Contemplating if I should go to the hospital or not.😣😣😣😣😣😣😣