Hello.
What you are going through seems to be the side-effect of the injection that you had taken. Please note that in regard to Bipolar Disorder, medication which are mood stabilizers are provided. It is also important to note that these mood stabilizers are to deal with the manic thoughts and ideas.
Counseling along with medication is very important to deal and cope with the thoughts that occur in bipolar disorder.
Next Steps
At the earliest meet a psychiatrist and let him/her what is happening. Bipolar is classified into bipolar1 and Bipolar 2, it's important to understand both or even to understand whether you have Bipolar or not.
Health Tips
Try to understand more about Bipolar and it will help you to understand things better.