Oil Leaking from Exhaust

Hi

I have a 2007 Citroen C4 Cool 1.6

I have just noticed that my car has been leaking oil from the exhaust. It's been doing it for at least 2 weeks, but I have only noticed this morning. We have a shared car park and I thought it may have come from someone else, but saw this morning that it is definitley from my car and it is definitley oil.

Other than that, I have noticed my car also seems to "struggle", when driving it. I think it's mostly at higher speeds, like when I'm in 4-5th gear, although I cannot be sure. It feels like it's in the wrong gear for the speed (I'm in the right gear), making the noise and having a general hard time, and then suddenly it seems to get power and almost shoot off.

I have also noticed that I have been filling up quite a lot. I'm not sure if it is more than when I first got the car, but it is noticably more frequent.

It was serviced not that long ago, and it had it's MOT in January, where the bottom end of the exhaust was actually replaced.

Any ideas/advice/help would be greatly appreciated. Thank you.