The thing that really stood out from me from your post was "I know relationships require sacrifice"
That's a very interesting limiting belief. Sacrifice? Really?
Think about that word and what that means. Is that what you really want for yourself
If the energy in your relationship is sacrifice (expecially yours), then no wonder you feel down and unsatisfied. Interestingly you finish that sentence with "but I really don't want to sacrifice being happy and achieving my dreams just so he's happy."
I don't get the feeling that the 'sacrifice' is equal on both sides. Is that true?
Also: "He often worries that my new path will leave no room for kids. It makes me worry too how I will fit everything into my life. My parents often make me feel like I can't have kids and a career. I must do everything I want to before having children because once I have them, it is pretty much the end for me."
Why is having kids the end for you? I know plenty of smart, wonderful women who have children who are still able to live their dreams and be happy. I'm not saying there are periods when it isn't difficult. But the END? No. In fact for many I've seen it is the start of something new. They find strength and energy that they never knew they had before because of the love they have for their child. They have to succeed even more!
If having kids is the end, why isn't it the end for both of you? I get the feeling that you feel you have to give up everything for the sake of the relationship, including your wants and dreams and stay at home with the children, so he can have his glittering career. Being a full-time mum is fine if that's what you want, but I really get the feeling you want a career as well. and that's great and achievable with the right support.
If you've been with this guy all your adult life then I imagine it's hard to imagine a different kind of relationship, where your needs and dreams are valued and supported. Where instead of sacrifice, you get mutual support, nurturing and encouragement. I'm sure there are good times, but I'm also sure that there is a long undercurrent of your needs being dismissed.
Don't blame your bf totally for this btw! He might be dismissing your needs, but you are also allowing that to happen. Take a look at where you are giving away your power in the relationship. You might be surprised. When you start to stand up for what you want, passionately with conviction, either he will accept it and change himself, or he will resist at first - then accept it, or you will go your separate paths.
I could have written a very similar post to yours when I was 25. I was in a non-supportive relationship, in a job that was wrong for me. I didn't have a good relationship with my parents. My uni friends had all drifted away. I was surrounded by a lot of negative people who didn't believe in 'rocking the boat'. Was I depressed? Probably. Because I was trapped by my own negative beliefs about the world. I didn't believe I was worth anything, that my dreams and needs weren't important. That I had to sacrifice my own feelings because someone else 'needed' me.
Personally I think meds are a last resort rather than a first. Some kind of therapy (but the right kind), not the talking version that just stirs everything up without resolving it can be really beneficial. You want something that is able to get to the root of why you feel the way you do, and helps you remove limiting beliefs.
Not sure if you have read Steve's book, but have a look at what he says about Truth, Love and Power. I'm guessing you are out on all three principles.
summary of principles here:
Pre-order Personal Development for Smart People
sample chapter here:
http://www.stevepavlina.com/personal...le-chapter.pdf
and btw 25 isn't old! At 25 I started over again and don't regret it for a second.