[verb (dictionary form)] + わ + [same verb (dictionary form)] + わ [verb (plain)] + わ、[verb (plain)] + わ [i-adj] + わ、[i-adj] + わ [na-adj] + だわ、[na-adj] + だわ
わ~わ strings things together in a rush, to say there was far more than you'd expect. It goes after the plain form, and its commonest shape repeats one verb in the dictionary form: "it kept on and on".
The verb stays in the dictionary form even when the story is in the past. The pattern is casual and loud – amazement or exasperation – and men and women both use it.
With two different verbs or adjectives, わ~わ lists things that piled up on each other. A noun or a な-adjective takes だ before わ. Each item usually has its own topic with は.
When a result follows, the last わ usually takes で. That use has its own point, わ〜~わで.