Zoloft help!

I am taking 50mg zoloft for postpartum issues. Just had a baby in July. I've had to start off with lower doses and increase every few days because the first full dose gave me very undesirable side effects.

So last night I upped my dose to 25 mg and this morning I felt those same side effects. Very dizzy and groggy. Agitated/angry. Kind of out of it feeling. Higher anxiety.

I take my dose at night before bed and feel off the whole next day until early evening then feel fine or at least better. Does this mean its not working for me? Scared to take my dose tonight because I fear of feeling the same way tomorrow. :(

Should I maybe change when I take it so the side effects hit at the time I'm asleep instead of when waking up? Since I feel better in the evenings or is that because its close to being out of my system and why I'm not feeling the negative side effects?

Funny thing is I have been on zoloft on and off since i was 18 (now 35) and never remember experiencing the negative side effects so extreme before. I've always loved it because it has worked so well with my anxiety, social anxiety and depression. Dont understand why my body is reacting this way this time.

I haven't yet reached the full 4 weeks for it to take its full effect of good benefits, so would hate to stop it if this will go away in the next 2 weeks and start making me feel better. Have any of you pushed through the difficult first few weeks and it be worth it?

Also my psychiatrist recommended trying lexapro but I'm so nervous to start something I've never taken before but would hate missing something that could potentially help me in the long run. What are yout experiences with lexapro for anxiety and social anxiety?

Thanks for any insight and advice you can give.