Hello Heather :) I promise I am not stalking you, but I do tend to read any of the mental health posts!
No, you would not necessarily feel depressed or anxious 100% of the time. You would have some good times and some bads, but you would more than likely know that you do not feel like yourself and did not like how you felt a lot of the time.
I cannot tell you how many times I have had people tell me that they 'did not have a reason to feel depressed.' Some people have situational depression because of a loss or something, but some people have depression just because. Our feelings just are, and there is no right or wrong to them.
As to whether you need meds, you can talk about that with your therapist or with a doctor. Therapy can definitely help, but it can take a while. You could possibly take something for a while (in combination with counseling), just to get you back to par, and then stop it when you are feeling better (not cold turkey though, you have to wean yourself a bit). I went on Zoloft for about 3-4 months after Jack was born. I was nursing him, and that is safe to take while breastfeeding. Like I wrote above, I just did not feel like myself and didn't feel like I was able to give my best to my son or my husband. After a few months, I felt better and slowly stopped taking them. And, though I am sure you know, let me say: Anti-depressants are not happy pills. Their purpose is not to make you ridiculously happy, but rather to bring you back to a normal level of functioning. And just because you may need them for a while, it does not mean you will need them forever. And it in no ways means you are a failure as a person, mother, or wife if you are depressed or need meds. (These are all misconceptions that I hear.)
If you are looking to go a drug-free route, I recommend these things, though all can be hard when you have kids: Exercise has the same level of benefit as a low-dose anti-depressant. It is a natural mood enhancher. Also, taking care of yourself by getting enough sleep and proper nutrition. If your body is well-fueled, it will run better. And get support where you can, through the moms group, family, friends, etc. Get some time away from the boys every once in a while; my MIL watched Jack for a few hours today, and I felt almost rejuvenated from it and couldn't wait to get him back.
I hope you start to feel better soon and have a fantastic vacation!