There is this quote I once read, I think it is by Ibn Qayyum, 'If after a sin you feel darkness in your heart, it means there is still light. Because only light feels darkness'.
It means you still have iman, and now you need to do amal (action) on this iman by sincere repentance and never missing your salah again. There is that hadith, we are all sinners, and the best of us are those who repent with true sincerity.
That attitude could be called heedlessness, which can lead to laziness or negligence. If we be negligent or heedless with our salah, what not to say we'll have that same attitude with every other aspect of our life? I think you should read about the importance of salah, and most importantly why *you* need it, as Allah swt does not need our worship in the slighest, we are in dire need of worshipping Him.
We all need to make salah a part of our life, sometimes at first it can be bit like 'fitting' it in there or 'squeezing' it here, but soon enough you'd find you just can't live without salah and something will just compel you to get up and pray.
That takes time though and making sure you stick to your prayer, you'll feel much better for it as well.