Please help me with this problem i have with a friend...?

I've been friends with Jarod for about 4 years now, and we were always in the same group of friends. But now theres only me and him. About 2 months ago a transfer student moved to our school, and he approached this student and became friend with him..sooner Joseph became apart of our group...Everything was good and Joseph and i didnt like each other that much at the start...But we got closer and tighter...Now theres only me Jarod and Joseph in our group...Recently i felt like Jospeh and i got really tight and became close friends..we now call each other bros and do thing together..Same goes with Jospeh and Jarod but Jarod doesnt participate in our go out events cause he always has an excuse to not come,,,and Jospeh and i are really rebellious and Jarod isnt..Recently i've been getting this feeling that Jarod is replacing me with Joseph and he isnt talking much toi me anymore and he deosnt wait for me to hang out with them anymore...so i just stay in the library and leave them alone together cause i feel unwanted and then Jarod and Joseph have their own jokes and convos that im not apart of...Like in facebook in every posts that Jospeh posts me Jarod always commetns on it and buts in...and Jarod posts things on his wall but not me? I dont know whats going on and i dont know what to do? :(