1) You can contract HIV from unprotected sexual relations, injecting a used needle, blood transfusion (not common in US), or from mother-to-child (child birth or breast feeding)
2) It is unwise for you to unprotected sexual relations, that is where most HIV cases can be linked back to
3) I am not a medical professional, but I would place you at MEDIUM risk, being you did engage in a low-risk practice of anal sex.
4) Mothers can give HIV to their child through breastfeeding... If a mother is having unprotected sexual relations outside of a committed relationship, she should REFRAIN from breastfeeding
5) ALWAYS use latex condoms if you must have sexual relations... Abstinence is the best way to protect against any STD and LATEX condoms are the second best way.
You should not panic unless you know the person you egaged in sexual outercourse with is HIV positive.
I recommend you get an HIV test 3 months after the first encounter and the 3 months after your last encounter with the person, that is the only way to know if you are in fact HIV positive.
Do NOT breastfeed or have any other unprotected sexual activity with ANYONE until you know you are HIV negative.
If you have received a NEGATIVE diagnoses after a 3 month period, DISREGARD the information I have listed above.
For more information, consult your family physician. I am not a medical professional and I do not have any experience in the medical field.
Please see a doctor if you feel you need to. Never panic until you know for sure!
I hope my response helped, have a good night and God Bless,