HELP- ranting

So before I got pregnant I weighed 135 & I’m 5’6. I didn’t eat the healthiest all the time but I tried my best. I was a vegetarian for a little over a yr before getting pregnant but my OB kept saying I wasn’t getting enough protein so I started eating meat again. ANYWAYS I’m 20 weeks and I’ve already gained 20lbs and I know it’s not all baby weight. I use to work out 2-3x a week and now I never work out. I’m just not motivated but I hate how I’m gaining weight and I really want to change my habits but don’t know why I haven’t or why it’s so hard just because I’m pregnant.... ANY ADVICE?? I just felt like being pregnant is when I should want to work out and be healthy but it’s total opposite for me. This is my second pregnancy btw and for my first I was THE SAME. Besides the vegetarian part pre pregnancy. I gained 60+ lbs and worked it all off after