When someone says 'Get on your feet ....', the speaker thinks that person is not doing enough. Maybe lazy, maybe just sitting around, or perhaps just showing no interest. The speaker is saying, 'get going'/'get started'/'move yourself and start doing something'
In the lyrics, the speaker is saying, 'Start doing something to prove your love', 'get out of neutral and do something to prove your love'. In other words, you've done nothing up to now so how about showing some interest and actually prove your love to me.