Has anyone experienced thisšŸ˜”

About a month ago these random thoughts came out of no where one night about my relationship me and my SO have been dating for about 4 years now, I love him so much literally more than anything us breaking up terrifies me and make me want to cry... Iā€™ve always been a worrier and over thinker a ā€œwhat ifā€ thinker. the thoughts started off as ā€œwhat if weā€™re not in love and just infatuated with eachotherā€ and moved to ā€œwhat if Iā€™m falling out of love himā€ and then to ā€œwhat if heā€™s getting bored of meā€ I literally couldnā€™t get them off of my mind I would go online and read forums and stuff constantly for a while Iā€™d be ok bu then theyā€™d come rushing back... it was so debilitating I couldnā€™t eat for almost a week I would cry all the time, I eventually went to the doctor and asked what she thought and she said it sounds like I have generalized anxiety disorder and recommended i should try CBT. The person hasnā€™t called me yet so idk what to do rn that was about about 2 weeks ago, last week it felt pretty much normal I saw him last Saturday and everything was normal I was so happy with him, weā€™re in somewhat of a LDR and only get to see eachother every 2 weeks so it sucks and is really painful but heā€™s worth all the pain and tears to me... a couple days after I had to leave the thoughts werenā€™t really bugging me but today they came flooding back and itā€™s all I could think about all day I was accusing him of being bored of me and I canā€™t shake the feeling that Iā€™m losing feelings for him when I know Iā€™m not bc just the thought of me losing feelings and breaking up with him makes me sick and want to cry..šŸ˜¢ I donā€™t know what to do.. has anyone experienced this before they just came out of ducking no where..ugh I hate them bc I know I love him I just want them to go away, my mom tells me it may just be my relationship changing which she said that itā€™s suppose to it can seem scary and make u think something is off but the relationship is just transition? Is this possible are u suppose to feel the same as when the relationship began? Could this be my anxiety? I just want these thoughts to go away. Yes Iā€™ve talked to my bf and heā€™s so supportivešŸ˜”ā¤ļø Iā€™m so blessed to have him he told me that heā€™ll be here no matter what and rhat he knows I love him just by the way I act and if I didnā€™t I wouldnā€™t be here.