What do I do?

I have terrible anxiety to where it's taking over my ability to think clearly. Sometimes I have bad thoughts, and I always cry myself to sleep. I pray every night that it will just stop, but it never does. I have a boyfriend, we've been together for 3 years. My anxiety has taken over and I can't help but overthink everything. I do trust him, but my head says what if he finds someone better, what if he gets this new job and he starts to like another girl, what if I lose my best friend and I can't get him back. My overthinking causes arguments, and I end up crying myself to sleep. I try so hard to be a good girlfriend, but I feel like I've failed because of my anxiety. I won't ever be good enough for anyone or anything. I used to have such a big imagination, and I had this amazing beautiful future planned ahead for me. Now it's like the future doesn't exist. I can't think straight enough to even imagine my future. I want to be here, but at the same time I'm so miserable and I just want it all to stop. I want to go back how I used to be, a normal girl that didn't have to fake her smile. I want to feel happy again. I want to feel that urge to push further. Someone please give me advice. I really need help. I'm on 3 anxiety pills, nothing is working. Thank you if you read this, I appreciate you a lot.