I Feel Like I'm Labouring in Vain.

Good day madam, my name is K**. I am 30 years old. I have this girl I have been dating for four years now. I have been the person taking care of her university's bills with the intention of getting married to her. She is such an amazing lady with a good heart. Her family knows me the same way my family knows her.

There is this lady that calls herself a prophet, I don't want to judge the source of her power because am not God. She told her l will not get married to her, that in fact I have another girlfriend somewhere which is a blatant lie because I don't have another girlfriend beside this lady in question, and my woman debunked it immediately she told her that because she knows I do not have another woman.
Since that day she hasn't been herself and I also feel like am labouring in vain but am so addicted to her likewise her to me, but words from the woman has really affected both of us. Please advise me. Thanks

Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world.1 John 4:1 ESV

Some prophets and pastors speak out of their emotions, some out of their own interests, some out of your own fears, and some based on the word of God.
Not all prophesies are genuine and from God, and this is why it is very very important that anyone who desires to venture into marriage must have a personal relationship with God and a personal altar for intercession to avoid being deceived and manipulated by some of these hungry and fake pastors and prophets who are looking for ways to survive.
Your convictions in a relationship supersedes the perception of any pastor or prophet.