I can definitely relate to your post and your last sentence/paragraph in particular. After several failed attempts to discontinue the Lexapro and/or switch to a different SSRI (primarily due to the discomfort & intensity of the brain zaps)... I have finally managed to "successfully" switch from 10mg of Lexapro to 20mg of Celexa daily.
Same as you, mood wise I feel good (or at least okay)... but my brain is also in "over drive and the rest of me can't keep up"! I have ADHD and OCD and often "joke" that where one leaves off... the other picks up! I can clean 1/4 of my kitchen from top to bottom (taking several hours)... but then loose steam and/or interest in finishing the rest of the kitchen. For me particularly, multiple, racing thoughts are a constant, even when I was on Lexapro (or previously Zoloft)... so much on my "to do" list, yet I never seem to have enough time to get any "one" thing completed to my satisfaction... but several things "semi" completed (just not enough to "mark off" the to do list)... which perpetuates my OCD cycle of ruminating or obsessing on all that still needs to be done.
Like you, I've noticed that since switching from Lexapro to Celexa, I am constantly cold... and I too am the person who is constantly "running hot". As far as appetite, I've noticed that I'm actually hungrier than when I was taking Lexapro (and I also take 10mg of Adderall in a.m. & noon for ADHD). Hot flashes, feeling warm all the time and loss of appetite were the first side effects I noticed within a few days of starting Lexapro.
I don't know that my post helps any, other than to reassure you that you're not alone, and your body's response is not "weird". I'm still not sure if Celexa will work better for me than the Lexapro did... but I was never quite sure if the Lexapro was really working or not. The Adderall helps me focus and reduces the overall "quantity" of racing thoughts, but it also increases my "level" of obsessiveness slightly (i.e. I'm a paralegal... attention to detail is important... but too much attention to every minute detail becomes overwhelming and occupies more of my time than I'd prefer).
As far as your BF and co-workers comments, you can take them into consideration, but should also try to balance them with your own feelings and observations regarding your moods (how you feel internally vs how you act & others perceive you externally). How you personally feel should be most important... but we DO have to co-exist with others and how we act (regardless of how we feel) does have an impact on our personal and work relationships. I have hated how physically "dependent" I've felt on Lexparo and definitely resent the withdrawal symptoms (along with the cost of the medication)... so I really want to give Celexa a chance. But I've also considered the possibility that Celexa won't be as effective and wondered if I'd be willing to go back onto Lexapro... in spite of how hard it was to discontinue. I'm only 5-6 weeks off Lexapro and on Celexa... so I guess I'm in a similar situation as you... so happy to be out of the "withdrawal" phase of Lexapro... but still waiting to see if Celexa will help my OCD symptoms.
Best wishes to you! I've been on this antidepressant/medication "merry-ro-round" or "roller coaster" for 10+ years. Was medication free for several years but found that the amount of mental energy expended trying to control my OCD/ADHD/anxiety symptoms became exhausting... and decided to resume medication. The meds help quite a bit, but it is definitely frustrating to find the right balance of meds vs self recognition/control/coping mechanisms to deal with the symptoms and normal daily stuff... and all the "what ifs" that come along with taking this med or that med or no meds... again the "merry-go-round" that's just not so "merry".
Please let me know if I can offer any other assistance or support!