I Am Taking Lexapro, 15 Mg Every Night Since 3

I am taking Lexapro, 15 mg every night since 3 years ago. A week ago, another doctor prescribed Phentermine, 30 m after breakfast. I only could take it 2 days. I felt nauseous, (threw up day and night) and had a bad headache.. I stopped the phentermine... But I am still fat. :( Should I give it a try? Is it safe? was that normal and it will go away?? or my body was telling me those medications are in conflict and therefore they're not safe together? Thanks!