Hello everyone,
I am a first-year PhD student, and I started my PhD in October. I started with a PhD proposal and due to many disagreements with my previous supervisor on the proposal after my arrival to the UK, we decided to change the topic. She said my proposal is "easy and anyone can do it!" Accepting to change the project at that time was a mistake! The first semester was wasted working on topics related to my previous supervisor's area of interest, but by the end of the semester in December, I was fed up with her perspectives, personality and with imposing her ideas on me. I decided to change the supervisor, and I would never regret that. In January, I decided to go back to working on my own proposal, and I started working with a new supervisor, who is open-minded and who liked the research project as it is. By coincidence in the end of February, I came across a PhD thesis which was submitted last semester and is very similar to my PhD research questions and objectives. I decided to be honest with my new supervisor about it. She asked me to write a new proposal, and she left it totally to me to choose what to do. Since then, I have researched different topics and found myself interested in different things. One of them is somehow related to my first proposal but am still confused about how I can do it (methodology, theoretical framework, etc.). The other ideas I have are totally different from my first proposal, and I conducted a pilot study about one of them. When I review the literature, I wonder whether my different ideas are really original or not! I can hardly maintain my interest in one of them and stick to. I feel lost. I started my PhD six months ago, and have not really done any real progress so far! I have to start a project in April. What should I do? How can I choose one of the topics I am interested in?

You are to be congratulated for your original stance over your first supervisor and pursuing your favoured topic.
That took real guts and you should be proud of yourself for that.
It's really bad luck that someone else beat you to it.

The most important question is whether you have got over the disappointment or whether it is still messing up your thoughts?

My advice is to follow the topic which most interests you. Ask your supervisor for their opinion on originality and present the case for both sides.

Thank you for your stimulating comment. Sometimes I think that I got over the disappointment, but other times I feel it is my mistake since I accepted to make a change to my original proposal and it is me who should bear all the consequences. I am in my twenties so I am mature enough and I should have insisted on the "no answer" instead of accepting to change the proposal. I still feel guilty in a way or another especially that 4 months of my PhD were wasted. Honestly, what still messes up my thoughts is her repeated words "you are wrong". I have many ideas now and I carried a pilot study for one of them. I sometimes feel excited about all of them. Other times I have this voice inside me saying "what if I am wrong now! I could be wrong"!! My new supervisor asked me to write a new proposal and send it by the 6th April, so we will not have any discussions until the proposal is sent. I have many interests, but sometimes the desire to carry out something different from other works hampers me. When I review the literature, I feel "everything is done! We know all the answers! Will I just end up with a different case study and new evidence"! Is that all what I want! I always find the answer "no"! I do not want to repeat the same things others said! To some extent, I feel down by not making any real progress although I do not show that to my new supervisor and I always try to sound as much confident as possible. Last time I told her that reading lots of articles about different topics is progress by itself since the PhD is a journey to help me learn! Inside me, I know this is not enough because I will be judged on the work I produce not on the reading, and some students who started in January made more progress than me! I am usually confident, but this time I am not sure!

Trying to come up with something original is part of the process and with it comes the constant fear that what you have done is wrong or irrelevant. Not sure you can avoid that risk I'm afraid.