You can & should have a termination if that is what you need to do.
I had a contraceptive failure a few years ago & fell pregnant when my youngest was just 5mths. There was no way I could go ahead with the pregnancy. The first 2 took a huge toll on my body & I wasn't ready to go through it all again.
With the support of just pone friend & my dh I terminated the pregnancy. No one in my family even knows, as they are all very much ante choice & would accept what I did.
It did confirm for me that 2 children is enough. So I have no plans to extend my family.
You can & should do this, if that is what you want.
First stop is to see your GP. Explain that you are pregnant & don't want to be, they will know that it is urgent, as to how far along you are. Let them set the wheels in motion for you.
Have the termination
Dump your partner
Are you medicated for the bipolar? If not, consider doing so. If you are, maybe you need to review your meds if you are prone to making bad choices?
Get on with your life, no regrets!
I don't know much about Bipolar, but I am here to answer an Qs wrt the termination.