Get in shape while pregnant?

Hi ladies. Please no judgment. I know the ideal woman would get her in best physical shape prior to getting pregnant but well, it just didn’t happen that way. I would not say I’m severely out of shape I go to the gym a few times a week I’m 5’1’’ 133 lbs. I just found out I’m pregnant! Very excited have been trying over a year! Then my mom tells me she gained 50 lbs while pregnant with me. That has scared me terribly. I know I should not go crazy working out and doing a lot of stuff I didn’t do before, but what’s safe to improve my body and health during pregnancy? Also the though of wearing a swimsuit already makes me want to puke now knowing I’ll be 4 months pregnant around summertime is scaring me even more. I’m worried I won’t be able to enjoy summer activities because I’ll be too embarrassed and be a drag on my husband. My normal routine used to consist of eating shitty fast foods half the time and drinking alcohol in the evenings and coffee throughout he day. I will be doing none of these things any longer so I’m sure it will help some. Is it possibly to safely lose weight and/ or tone up during pregnancy? Advice please? Thanks ladies!