2nd baby very scared

Hi im very scared ive just found out im pregnant with my 2nd child my first daughter is 3yrs but her Dad and i split up when she was about 1 it was very traumatic for me tried to keep her out of it. Started a new relationship but its been hard for about 2 yrs as my first daughters dad kept getting involved. My now current bf and i had breaks because of my daughters dad so my current bf slept with a 16 yr old and when we got back together he told me in detail might i add it put SO many doubts in my head. Now im pregnant with his child im scared cause first of all im a type one diabetic, and as we werent trying i went back on roaccutane for my skin (only took one tablet the month previously) and now ive had to take antibiotics for my eye that the docs arent 100%sure on risks for baby. Im so scared there may be something wrong with bubs and it will be my fault :( what do i do? What would you do in this situation? Might i add my current boyfriend and i arent the most stable of relationships. We both are angry at each other for things we cant change. We're trying to be better but sometimes it just comes out. :( im feeling really depressed and unhealthy :( sorry in advance for my atrocious grammer hope all this makes sense.