Sex not what it used to be

So we use to be crazy about sex. Almost every night we had to do it. He was just as horny. He would play with my feet and get horny. I'm 28 weeks pregnant and now we maybe have sex once a month. He says it's cuz he's tired and wants to sleep. He says it's nothing to do with me.... he's just tired. Idk maybe it's the hormones but I am definitely worried about it. I love sex I feel like I wanna burst the longer we go without it. I also get a short temper the longer we go without it. So that does NOT help the situation. We do have a house full all the time. He has a 12, and a 7 year old that we have monday through Thursday and our son who is 18 months. Hell im tired too i cook, clean, work full time, and pregnant and i still want to have some us time at the end of the night..... I just need some advise am I over reacting