Sleep regression

So my baby was sleeping through the night at about 3 months finally, after having horrible colick and not sleeping more than an hour. At 4 months she started to get up a couple times a night and I figured that was normal 4 month sleep regression. Well it’s only gotten worse. She’s 5 1/2 months now and getting up 4-6 times in the night. Im feeding her 2-3 of those times and I’m exhausted. I don’t know if because I get up and attend to her now she’s learned that I’ll do that, I’m thinking maybe I need to let her cry a little. I’m so frustrated. Especially since I just found out I’m pregnant again despite being on 2 types of birth control and I’m extremely stressed so her not sleeping isn’t helping. Not to mention how tired I am being pregnant. I know she’s a baby but it’s just frustrating because I know she can sleep through the night. And I honestly didn’t think the regression would last this long. Any tips to help? We have the same routine every night too bath, pjs, bottle, bed.