Lindsay Lohan's Baby Bump or Breakfast Burrito?

Lindsay Lohan's definitely showing ... mixed signals.

She's still hanging with friends on a yacht in Sardinia, Italy ... and this time we see what appears to be a bump ... of sorts.

You'll recall Lindsay went on a social media tirade -- and teased on Twitter she's pregnant -- after her blow-up with fiance Egor Tarabasov. Last time we saw her, Lindsay was smoking a cig, which is a major no-no when there's a bun in the oven.

News she's pregnant hasn't been confirmed ... and for all we know she coulda just been trying to stick it to Egor with a guilt trip. Interestingly enough ... sources tell TMZ Lindsay has privately told some family members she's preggo.

We'll anxiously wait for the second trimester.