Anxiety is going to ruin my relationship

This is my first time to post to something like this. Iv been in a complete state of panick, worry, nervousness the past few weeks.
The thought came into my head one day "what if you don't love him as much as you say" reguarding my boyfriend, might I add he is the best thing that's ever happened to me. I know I love him and just please remeber that when you read on. That thought came and went when I looked at a few pictures of us and felt reassured i did love him and I laughed it off. It happend again a few weeks later and again I laughed it off.

Everything was fine up until I had that thought again this time I couldn't get it to go. I started to panick and overthink everything. What if I don't love him? What If I have to end things and that's when all my problems started. I can't sleep, eat, I feel nervous and anxious to talk to him and see him. I know I love him and I keep telling myself that but I can't seem to get the thoughts to go. I told him everything and being as amazing a person he is he told me everything will be okay. It got worse and I was forced to tell my parents, they told me it's fine the honey moon phase is over and you won't be all loved up All the time and I believed them. But I still couldn't get rid of the nerves and worry and anxiety. I can't loose him he is my everything, I care about him so much. Everything got worse and I broke down to a friend in work and told her everything. She told me this will now go away unless I get help so I did . That day I went to my doctor and broke down and told him everything. He told me I had anxiety and depression and prescribed me antidepressants. I took them for two days and felt amazing, back to myself again and excited to see my boyfriend. I know this had to be the placebo effect because anti depressants don't work this quickly. But it didn't last long anyway about a week after I woke up during the night with severe heart palpitations and woke my boyfriend up with fright. He was there for me and comforted me. It all started again from there. But now I feel nothing when I look at him, empty and terrified because I can't loose him I just can't please someone tell me this has happened you and I will be okay. We have talked about marriage and kids and I can't see myself with anyone else but him. I feel like I'm loosing my mind. I thought about ending it all but that would mean I would still be loosing him in a way and I thought of how he would feel if I wasn't here. I'm back on the antidepressants now the last 3 days and Iv come off my contraceptive pill as I did a lot of research and found that a lot of women on my pill ended up with depression and anxiety as part of side effects. Hopefully someone can give me some person experiences and let me know I'm not the only one. I won't give up I can't because I can't loose him he's the best thing that's ever happened me I'm gonna stick it out and wait for my feelings to "switch" back on I know how stupid that sounds but it's my only hope