Facebook ads

I have an evergreen funnel and I get leads in using Facebook ads. From Jan-the end of March I had great results and as soon as April hit my funnel isn’t converting well, my ad costs are really high. I invested in a facebook ads course to help me learn more about them and although I like the program the funnel isn’t converting like before. I’m feeling frustrated and don’t know if it’s my funnel that’s not really working or my ads? I felt like I have proof of concept since I have 160 ppl in my program, but now I’m starting to think maybe my funnel needs tweaking. I did tweak my sales page and some emails over the weekend but I’m wondering if I need to change everything, or if I just need to focus on my ads. Please help!