I have finished my master's in mathematics from an UK university with a first class distinction. I have always wanted to do a PhD in mathematics. But my supervisor is saying that the recommendation letter that he is going to write may not be the most positive one. I feel devastated, since he didn't mention any reason throughout the supervision. Now, to continue my study in mathematics, I have two options in my hand
(i) To apply for PhD without supervisor's letter of recommendation preferably from usa.
(ii) To do a second master's degree, I prefer from Germany.
I was wondering, what are the chances for me to get a PhD in a decent university, and what are the chances of being accepted for a second master's degree from Germany in a good university. I feel so stuck right now, it will be great if you can help me with this!
Edit: From a second masters degree I am expecting to do a serious research on my topic so that I can get a strong lor from my supervisor for phd